ARTICLE | doi:10.20944/preprints202101.0473.v1
Subject: Medicine & Pharmacology, Allergology Keywords: molecular methods; virus; pandemic; Coronaviridae; COVID-19, diagnosis; UK variant; B.1.1.7 variant; 501Y.V2 variant
Online: 25 January 2021 (10:32:38 CET)
Starting from early 2020, the COVID-19 pandemic has caused a morbidity and mortality excess worldwide. Containment strategies rely firstly on rapid and sensitive laboratory diagnosis with molecular detection of the viral genome in respiratory samples being the gold standard. Reliability of diagnostic protocols could be affected by SARS-CoV-2 genetic variability. In fact, mutations occurring during SARS-CoV-2 genomic evolution can involve the regions targeted by the diagnostic probes. Following a review of the literature and an in silico analysis of the most recently described virus variants (including the UK B 1.1.7 and the South Africa 501Y.V2 variants), we conclude that the described genetic variability should have minimal or no effect on the sensitivity of existing diagnostic protocols for SARS-CoV-2 genome detection. However, given the continuous emergence of new variants, the situation should be monitored in the future, and protocols including multiple targets should be preferred.
ARTICLE | doi:10.20944/preprints202209.0390.v1
Subject: Biology, Other Keywords: SARS-CoV-2; COVID-19; asymptomatic; seroprevalence; Delta variant; Omicron variant; vaccination
Online: 26 September 2022 (09:41:01 CEST)
A significant proportion of SARS-CoV-2 infections in Africa are identified as asymptomatic, facilitating the silent spread of the virus especially in populated urban cities. With the surge of the highly transmissible Omicron variant, the inclusion of asymptomatics in epidemiological surveys is key in estimating true infections and seroprevalence in the population. The aim of the study was to determine seroprevalence, active infection and circulating variants in Accra, the capital city of Ghana during the Omicron wave. The study was a cross-sectional survey conducted in 22 municipalities in December 2021. Naso-oropharyngeal swabs and serum samples were collected from 1027 individuals aged 5 years and above, for detection of infection by RT-qPCR and estimation of total antibodies using the WANTAI ELISA kit. Our results show 10% SARS-CoV-2 prevalence, with the Omicron and Delta variants accounting for 44.1% and 8.8% of infections, respectively. Omicron was most prevalent (48.9.%) among the 20–39-year-olds. Asymptomatic individuals accounted for 75.2% of infections. Seropositivity within the population was 86.8%, with the 60+ year group having significantly higher likelihood of exposure (OR 10.22: 95% CI: 3.51-29.73; p<0.001). This high seroprevalence appears to have been as a result of increased vaccination among this group (OR 2.7: 95% CI 1.78-4.09, p < 0.001). The high seropositivity of SARS-CoV-2 in the capital could be a good indication of herd immunity among the population and while the low infection rate supports the role of vaccination in reducing viral transmission.
ARTICLE | doi:10.20944/preprints202012.0387.v1
Subject: Life Sciences, Biochemistry Keywords: next-generation sequencing; database; variant annotation; variant classification; data management; clinical genomics
Online: 15 December 2020 (13:14:21 CET)
The rapid evolution of Next Generation Sequencing in clinical settings and the resulting challenge of variants interpretation in the light of constantly updated information, requires robust data management systems and organized approaches to variant reinterpretation. In this paper, we present iVar: a freely available and highly customizable tool provided with a user-friendly web interface. It represents a platform for the unified management of variants identified by different sequencing technologies. iVar accepts, as input, VCF files and text annotation files and elaborates them, optimizing data organization and avoiding redundancies. Updated annotations can be periodically re-uploaded and associated to variants as historicize attributes. Data can be visualized through variant-centered and sample-centered interfaces. A customizable search functionality can be exploited to periodically check if pathogenicity related data of a variant are changed over time. Patient recontacting ensuing from variant reinterpretation is made easier by iVar through the effective identification of all patients present in the database and carrying a specific variant. We tested iVar by uploading 4171 VCF files and 1463 annotation files, obtaining a database of 4166 samples and 22569 unique variants. iVar has proven to be a useful tool with good performances for collecting and managing data from medium-throughput
ARTICLE | doi:10.20944/preprints202208.0209.v1
Subject: Medicine & Pharmacology, General Medical Research Keywords: cluster analysis; SARS-CoV-2; Variant
Online: 11 August 2022 (06:01:14 CEST)
Viral variant analysis is a bedrock of the disease surveillance. When combined with temporospatial analysis variant analysis can further the knowledge of disease spread in a study area. This paper suggests a method to perform the analysis in an operational setting which will allow for real-time surveillance of viral variants and allow local public health professionals to rapidly respond to changes in the evolution of the disease. This method includes three main subprocesses: preprocessing, analysis, and rendering. This method can be performed across multiple software platforms. A use case is given in which it was found that this method helped a hospital system understand the spread of SARS-CoV-2 in Northeast, Ohio.
ARTICLE | doi:10.20944/preprints202104.0401.v1
Subject: Medicine & Pharmacology, Allergology Keywords: Colorectal cancer; personalized medicine; biomarker; variant
Online: 15 April 2021 (08:10:42 CEST)
Discovery of novel variants from data derived from local population provides confident targets for developing biomarkers for personalized medicine. Biomarker discovery would be an important tool in advancing and utilizing the concept of precision and personalized medicine in the clinic. We identified the need to generate high quality sequencing data from local population and understand the pattern of occurrence of variants in colorectal cancer patients. In this report, we used archived samples from Saudi Arabia and used Ampliseq Comprehensive Cancer panel to identify novel somatic variants. We report a comprehensive analysis of next generation sequencing results with a coverage of >300X. We identified 466 novel variants which were previously unreported in COSMIC and ICGC databases. We analyzed the genes associated with these variants in terms of their frequency of occurrence, probable pathogenicity and clinicopathological features. Among pathogenic somatic variants, 174 were identified for the first time in large intestine. APC, RET and EGFR genes were most frequently mutated. Higher number of variants were identified in left colon. Occurrence of variants in ERBB2 was significantly correlated with those of EGFR and ATR genes. Network analyses of the identified genes provide functional perspective of the identified genes and suggest affected pathways and probable biomarker candidates. This report lays the ground work for biomarker discovery and identification of driver gene mutations in local population.
REVIEW | doi:10.20944/preprints201911.0085.v1
Subject: Life Sciences, Genetics Keywords: mendelian disease; diagnostics; variant interpretation; variant prioritization; rna splicing; bioinformatics; machine learning; genomic medicine; effect prediction
Online: 8 November 2019 (04:07:16 CET)
Defects in pre-mRNA splicing are frequently a cause of Mendelian disease. Despite the advent of next-generation sequencing, allowing a deeper insight into a patient’s variant landscape, the ability to characterize variants causing splicing defects has not progressed with the same speed. To address this, recent years have seen a sharp spike in the number of splice prediction tools leveraging machine learning approaches, leaving clinical geneticists with a plethora of choices for in silico analysis. In this Review, some basic principles of machine learning are introduced in the context of genomics and splicing analysis. A critical comparative approach is then used to describe seven recent machine learning-based splice prediction tools, revealing highly diverse approaches and common caveats. We find that, although great progress has been made in producing specific and sensitive tools, there is still much scope for personalized approaches to prediction of variant impact on splicing. Such approaches may increase diagnostic yields and underpin improvements to patient care.
ARTICLE | doi:10.20944/preprints202007.0735.v1
Subject: Life Sciences, Genetics Keywords: Variant of Unknown Significance (VUS); Single-Nucleotide Variant (SNV); Variant Effect Prediction (VEP); Stacked Ensemble of Supervised Deep Learners (SESDL); Next Generation Sequencing (NGS); Alternative Allele Frequency (AAF).
Online: 31 July 2020 (06:13:53 CEST)
Pathogenicity is unknown for the majority of human gene variants. For prioritization of sequenced somatic and germline mutation variants, in silico approaches can be utilized. In this study, 84 million non-synonymous Single Nucleotide Variants (SNVs) in the human coding genome were annotated using consensus Variant Effect Prediction (cVEP) method. An algorithm, implemented as a stacked ensemble of supervised learners, performed combination of the 39 functional, conservation mutation impact scores from dbNSFP4.0. Adding gene indispensability score, accounting for differences in the pathogenicities of the variants in the essential and the mutation-tolerant genes, improved the predictions. For each SNV the consensus combination gives either a continuous-value pathogenicity score, or a categorical score in five classes: pathogenic, likely pathogenic, uncertain significance, likely benign, benign. The provided class database is aimed for direct use in clinical practice. The trained prediction models were 5-fold cross-validated on the evidence-based categorical annotations from the ClinVar database. The rankings of the scores based on their ability to predict pathogenicity were obtained. A two-step strategy using the rankings, scores and class annotations is suggested for filtering and prioritization of the human exome mutations in clinical and biological applications of NGS technology.
REVIEW | doi:10.20944/preprints202207.0051.v1
Online: 4 July 2022 (10:28:04 CEST)
For the first time in history, we have witnessed the origin and development of a pandemic. To handle the accelerated accumulation of viral mutations and to comprehend the virus' evolutionary adaptation in humans, an unparalleled program of genetic sequencing and monitoring of SARS-CoV-2 variants has been undertaken. Several scientists have theorized that, with the Omicron surge producing a more contagious but less severe disease, the end of COVID-19 is near. However, by analyzing the behavior shown by this virus for 2 years, we have noted that pandemic viruses do not always show a decreased virulence. Instead, it appears there is an evolutionary equilibrium between transmissibility and virulence. We have termed this concept “intermittent virulence”. The present work analyzes the temporal and epidemiological behavior of SARS-CoV-2 and suggests that there is a high possibility that new virulent variants will arise in the near future, although it is improbable that SARS-CoV-2´s virulence will be the same as was seen during the pandemic phase.
CASE REPORT | doi:10.20944/preprints202201.0177.v1
Subject: Medicine & Pharmacology, Allergology Keywords: variant effect maps; cardiac arrest; cardiovascular genetics
Online: 12 January 2022 (15:42:46 CET)
While genetic testing is becoming standard of care for patients with potentially inherited cardiovascular disease, the prevalence of uncertain results severely limits its utility. One promising approach is to generate variant effect maps that report the function of all possible variants in a gene prospectively. The proactive clinical application of these maps is nascent, and requires careful integration with current American College of Medical Genetics guidelines for variant interpretation. Here, we describe three pediatric cases of cardiac arrest or sudden cardiac death with variants of uncertain significance in calmodulin genes. We demonstrate the prospective clinical utility of a calmodulin variant effect map to inform variant interpretation, and therefore diagnosis and family care, in each case. This study was approved by the Stanford University and Vanderbilt University Medical Center IRBs. Consent was waived based on low risk of de-identified retrospective data collection per the IRB.
REVIEW | doi:10.20944/preprints201806.0191.v1
Subject: Life Sciences, Genetics Keywords: rare disease; functional genomics; genetic variant validation
Online: 12 June 2018 (12:36:08 CEST)
Many insights into human disease have been built on experimental results in Drosophila, and research in fruit flies is often justified on the basis of its predictive value for questions related to human health. Additionally, there is now a growing recognition of the value of Drosophila for the study of rare human genetic diseases, either as a means of validating the causative nature of a candidate genetic variant found in patients, or as a means of obtaining functional information about a novel disease-linked gene when there is little known about it. For these reasons, funders in the US, Europe, and Canada have launched targeted programs to link human geneticists working on discovering new rare disease loci with researchers who work on the counterpart genes in Drosophila and other model organisms. Several of these initiatives are described here, as are a number of output publications that validate this new approach.
ARTICLE | doi:10.20944/preprints202201.0333.v1
Subject: Mathematics & Computer Science, Artificial Intelligence & Robotics Keywords: Covid-19; Ensemble; Genome sequencing; Machine learning; Variant
Online: 21 January 2022 (15:17:58 CET)
Covid-19 has caused infections and deaths worldwide. While research in the field of Data Science has contributed good predictions of positive Covid-19 case numbers, this study's review of literature shows there is little research in the use of variants of the virus in predictions. We set out to define and evaluate novel variant features. We find that features relating to variant trends, thresholds and amino acid substitutions are especially powerful in two tasks. In the first task, predicting Covid-19 case numbers, accuracy improved from 71.53% without variant features to 82.12% with variant features. In the second task, predicting transmission severity of variants between two classes, we created a method to build some variable ensembles through selecting appropriate models that are generated with variant features. The test results showed that our ensembles are more accurate and reliable. One particular ensemble of 14 models correctly classified 90.91% of variants, outperforming other models including the popular Random Forest ensemble. In addition, as the variant features have represented more underlying information about Covid-19 pathophysiology, our ensemble methods use only a few data samples to achieve an accurate prediction. The ensemble of 14 models uses only 50 cases of each variant, an ability that could be exploited for early detection of highly infectious variants. These research findings may benefit public health professionals, policy makers, and the research community in the collective efforts to overcome this disease.
ARTICLE | doi:10.20944/preprints201807.0159.v1
Online: 10 July 2018 (05:36:05 CEST)
Background: Prostate cancer is a complex condition, in which both genetic and environmental factors concomitantly contribute to the tumor initiation and progression. Recently, HOXB13 has been proposed as a susceptibility gene for prostate cancer. Objective: So the current study was conducted to test the existence of potential variations in HOXB13 gene in Iranian men with prostate cancer (PCa) compared to benign prostatic hyperplasia (BPH) cases. Methods: The HOXB13 genetic status was screened in 51 samples, including 21 blood and tissue of PCa cases compared to 30 cases affected by BPH using PCR/sequencing. Then potential association between genomic DNA alterations in blood and tissue PCa specimens was investigated Results: Analysis of BPH tissues showed single nucleotide variations c.366C > T (rs) or c.513T > C (rs9900627) in exon 1, but not in exon 2. Evaluation of PCa tissues revealed two cases with both synonymous c.366C > T and c.513T > C variants and two cases with the synonymous c.366C > T variant in exon 1. The variants c.366C > T and c.513T > C simultaneously or separately were found blood samples of PCa patients. The novel variant c.127A > G in the exon 2 was detected in 1 PCa blood sample. Our analysis indicated a significant reciprocal correlation between HOXB13 mutation in tissue and blood in PCa cases (P=0.02). Conclusion: The variants in exon 2 of HOXB13 may influence the risk of prostate cancer. Also, evaluation of HOXB13 mutation may be considered as a novel marker for screening of PCa. Further investigations are warranted to evaluate the clinical significance of HOXB13 in Iranian population.
BRIEF REPORT | doi:10.20944/preprints202205.0018.v2
Online: 6 May 2022 (11:55:20 CEST)
The rapid emergence and worldwide detection of the SARS-CoV-2 omicron variant underscore the importance of robust genomic surveillance systems and prompt information sharing among global public health partners. The Omicron variant has rapidly replaced the delta variant as a dominating SARS-CoV-2 variant because of natural selection, favoring the variant with higher infectivity and more strong vaccine breakthrough ability. Also known as B.1.1.529, Omicron has four sub-variants, BA.1, BA.2, BA.3, and BA.4. Among them, BA.1 is the currently prevailing sub-variant, BA.2 is found to be able to alarmingly re-infect patients initially infected by omicron BA.1. BA.3 sub-variants is a combination of mutations of BA.1 and BA.2, especially in the spike protein. Today emerging is the BA.4, herein described and first detected in Italy, harboring a new mutation, specifically a deletion in the ORF 1 ab gene, corresponding to KSF141_del in non-structural protein 1 (nsp1), a critical virulence factor able to suppress host translation. The bioinformatics comparison analysis with the other three sub-variants pointed out that the deletion was not present previously and was never reported until now. Therefore, we can speculate that omicron BA.4; will become a new dominating “variant of concern” and might also break vaccine protection . On the other hand, we show that other proteins are mutated in the BA.4 in particular, seven mutations are recognized in the nucleocapsid (N) protein, the capability of five different types of rapid antigenic tests to recognize it.
COMMUNICATION | doi:10.20944/preprints202203.0010.v1
Online: 1 March 2022 (09:01:19 CET)
Rapid antigen detection tests (RAD) are commonly used for the diagnosis of SARS-CoV-2 infections. However, with the continuous emergence of new variants of concern (VOC) presenting various mutations potentially affecting the nucleocapsid protein, the analytical performances of these assays should be frequently reevaluated. One-hundred and twenty samples were selected and tested with both RT-qPCR and five commercial RAD commonly sold in Belgian pharmacies. Of these, direct whole genome sequencing identified the strains present in 116 samples, of which 70 were Delta and 46 were Omicron. Sensitivity across a wide range of Ct values (13.5 to 35.7; median = 21.3) were comparable and ranged from 70.0% to 77.1% for Delta strains and from 69.6% to 78.3% for Omicron strains. When taking swabs with a low viral load (Ct > 25), poor performances were observed for the Delta strains (20.0 to 40.0%) and, even more so, for Omicron strains (0.0 to 23.1%). Two devices failed to detect all samples (n = 13) containing Omicron strains with a low viral load. The poor performance observed with low viral loads is an important limitation of RAD, which is not sufficiently highlighted in the instruction for use of these devices.
ARTICLE | doi:10.20944/preprints202104.0643.v1
Subject: Engineering, Automotive Engineering Keywords: flexible rotating machinery; balancing method; speed-variant; acoustic feedback
Online: 23 April 2021 (13:18:55 CEST)
As rotary machines have become more complicated, balancing processes have been classified as a vital step in condition monitoring to ensure machines operate both reliably and safely. This is especially important for flexible machines which normally work at rotations speeds above critical limits. Imbalance is a common problem in flexible rotating machinery that can lead to extreme vibration and noise levels. This is one of the major reasons for studying various balancing methods applied to the vibration response of rotating machines. Recently, the relation between acoustic and vibration response during a rotary machine balancing process based on the Four-Run method has been presented for constant speed machines. This method cannot be applied to machines in start-up or shut-off. Hence, by considering the acoustic and vibration responses of a machine between its critical speeds, this research presents a new innovative speed-variant balancing method based on the original Four-Run method, named as "Peak to Peak for Critical Speeds (PPCS)". The proposed method consists of two major types of application: the first is in the Run-up of the machine and the second is in Shut-down. Experimental laboratory results show that the PPCS method can be implemented for speed-variant and flexible rotary machines during run-up or shut-down transient processes based on acoustic and vibration measurements. As a phase-less and a contactless method, the PPCS can be employed as an innovative and readily available method for condition monitoring in the future.
ARTICLE | doi:10.20944/preprints202103.0257.v1
Subject: Life Sciences, Biochemistry Keywords: SLC15A4; germline variant; familial colorectal cancer; whole exome sequencing
Online: 9 March 2021 (10:24:33 CET)
About 15% of colorectal cancer (CRC) patients have first-degree relatives affected by the same malignancy. However, for most families the cause of familial aggregation of CRC is unknown. In order to identify novel high-to-moderate penetrant germline variants underlying CRC susceptibility, we performed whole exome sequencing (WES) on four CRC cases and two unaffected family members of a Polish family without any mutation in known CRC predisposition genes. After WES, we used our in-house developed Familial Cancer Variant Prioritization Pipeline and identified two novel variants in the solute carrier family 15 member 4 (SLC15A4) gene. The heterozygous missense variant, p. Y444C, was predicted to affect the phylogenetically conserved PTR2/POT domain and to have a deleterious effect on the function of the encoded peptide/histidine transporter. The other variant was located in the upstream region of the same gene (GRCh37.p13, 12_129308531_C_T; 43bp upstream of transcription start site, ENST00000266771.5) and it was annotated to affect the promoter region of SLC15A4 as well as binding sites of 17 different transcription factors. Our findings of two distinct variants in the same gene may indicate a synergistic up-regulation of SLC15A4 as the underlying genetic cause and implicate this gene for the first time in genetic inheritance of familial CRC.
ARTICLE | doi:10.20944/preprints202103.0121.v1
Subject: Life Sciences, Biochemistry Keywords: Familial colorectal cancer; SRC; germline variant; whole genome sequencing
Online: 3 March 2021 (09:52:06 CET)
Colorectal cancer (CRC) shows one of the largest proportions of familial cases among different malignancies, but only 5-10% of all CRC cases are linked to mutations in established predisposition genes. Thus, familial CRC constitutes a promising target for the identification of novel, high- to moderate-penetrance germline variants underlying cancer susceptibility by next generation sequencing. In this study, we performed whole genome sequencing on 3 members of a family with CRC aggregation. Subsequent integrative in silico analysis using our in-house developed variant prioritization pipeline resulted in the identification of a novel germline missense variant in SRC gene (V177M), a proto-oncogene highly upregulated in CRC. Functional validation experiments in HT-29 cells showed that introduction of SRCV177M resulted in increased cell proliferation and enhanced protein expression of phospho-SRC (Y419), a potential marker for SRC activity. Upregulation of paxillin, β-Catenin and STAT3 mRNA levels, increased levels of phospho-ERK, CREB and CCND1 proteins and downregulation of the tumor suppressor p53 further proposed the activation of several pathways due to the SRCV177M variant. The findings of our pedigree-based study contribute to the exploration of the genetic background of familial CRC and bring insights into the molecular basis of upregulated SRC activity and downstream pathways in colorectal carcinogenesis.
ARTICLE | doi:10.20944/preprints202009.0602.v1
Subject: Medicine & Pharmacology, Allergology Keywords: COVID-19; Genomes; microRNA; SARS-CoV-2; Variant discovery
Online: 25 September 2020 (10:14:46 CEST)
Background SARS-CoV-2 has generated a life-treating pandemic and is the main challenge of this century. Some untranslated regions (UTRs) in SARS-CoV-2 genome, specifically leader sequence and transcription regulatory sequence (TRS) in 5’UTR, can be considered as Achilles' heel of virus. Leader sequence are found at the 5' ends of all encoded transcripts that highlights its importance. TRS can explain the host range and pathogenicity of coronavirus. However, our knowledge on the evolution and the role of UTRs in SARS-CoV-2 pathogenicity is very limited. This study is a pioneering attempt to unravel the evolution of key regions in 5' UTR of SARS-CoV-2 and discover the inhibitory microRNAs against 5' UTR of virus. Methods Evolution of TRS and leader sequence was compared between human pathogenic (SARS-CoV-2, SARS, and MERS) and non-pathogenic (bovine) coronaviruses. Profiling of microRNAs that can inactive the key UTR regions of coronaviruses, UTR-inhibitory microRNAs, was carried out. Findings We found a distinguished pattern of evolution in leader sequence and TRS of SARS-CoV-2, compared to the other coronaviruses. Mining all available microRNA families against leader sequences of coronaviruses resulted in discovery of 39 microRNAs with an acceptable thermodynamic binding energy against SARS-COV-2, SARS, MERS, Bat Coronavirus, or Bovine Coronavirus. Multivariate analysis demonstrated a distinguished pattern of binding of leader sequence of SARS-CoV-2 against microRNAs, with a lower binding stability. hsa-MIR-5004-3p was the only human microRNA that can target leader sequence of SARS and SARS-CoV-2. However, its binding stability remarkably decreased in SARS-COV-2 (-19.4 kcal/mol), compared to SARS-COV-2 (-25.9 kcal/mol). We found an insertion-type mutation in leader sequence of SARS-COV-2 that results in lower binding stability and escaping of viral leader sequence from hsa-MIR-5004-3p. Altogether, we suggest lack of innate human inhibitory microRNAs to bind to leader sequence and TRS of SARS-CoV-2 contributes to its high replication in infected human cells. On the other hand, mining of two hundred million deposited human genomic variants led us to discovery of 49 missense and splice-disrupt mutations in genomic structure of hsa-MIR-5004-3p. These mutations can negatively affect hsa-MIR-5004-3p function in preventing SARS-CoV-2 replication. Interpretation This study unravels the evolution of key regions in 5’UTR of SARS-CoV-2. Inducing microRNAs to bind to the leader sequence and TRS regions by drugs or food supplements can reduce virus replication. Enhancing the microRNA defence machinery against TRS and leader of virus has a potential to prevent SARS-CoV-2 infection at the first place. The mentioned strategy is rapidly achievable against COVID-19. Missense variation in genomic sequence of 5’UTR inhibitory microRNAs, such as hsa-MIR-5004-3p, can be considered as risk factor of COVID-19.
CASE REPORT | doi:10.20944/preprints202008.0669.v1
Subject: Medicine & Pharmacology, Clinical Neurology Keywords: Miller Fisher Syndrome; Guillain Barré Syndrome variant; Dysphonia; Dysphagia
Online: 30 August 2020 (14:41:29 CEST)
Miller Fisher Syndrome (MFS) is a rare variant of Guillain-Barré Syndrome (GBS). It is largely a clinical diagnosis based on the classical features of ataxia, areflexia, and opthalmoplegia. Its clinical evolution is most often favorable. However, other neurological signs and symptoms may also be present. Supportive laboratory studies (positivity of antibodies, CSF albumin-cytological dissociation and nerve conduction studies) are useful especially in uncommon presentations. We report a case of a 74-year-old patient who exhibited dysphonia and difficulty to swallowing previously to the classic triad of ataxia, areflexia, and opthalmoplegia, characteristic of MFS. CSF analysis demonstrates an albumin-cytological dissociation but anti-GQ1b antibody were negative. The patient has spontaneously and completely recovered after several weeks.
BRIEF REPORT | doi:10.20944/preprints202005.0466.v1
Subject: Life Sciences, Virology Keywords: COVID-19; SARS-CoV-2; variant; low pathogenicity; Singapore
Online: 29 May 2020 (12:47:07 CEST)
Number of confirmed cases of COVID-19 caused by SARS-CoV-2 exceeded 5 million as of May 21, 2020. Global average of the case fatality rate of COVID-19 is about 7% so far. There exist variations in case fatality rates among countries. Particularly, Singapore and Qatar have exceptionally low case fatality rates with 0.1% while France’s rate is almost 20%. Since no magic bullet treatment for COVID-19 exists, we investigated SARS-CoV-2 strains specific to Singapore in this study to identify a clade with low pathogenicity. Variant analysis revealed that a clade with variants ORF1ab L3606F, A4489V, S2015R, T2016K, and N P13L is common in Singapore. Based on our analysis of variants and historical case statistics, the clade is dominant in a recent surge. Therefore, we suggest that low case fatality rate of Singapore possibly is attributed to the clade. Although contribution of each variant to the low pathogenicity is not clear, L3606F alone does not accomplish such low pathogenicity from the comparison with case fatality data from Japan, where L3606F is dominant. Further investigation is necessary to conclude to validate this finding.
ARTICLE | doi:10.20944/preprints202209.0362.v1
Subject: Life Sciences, Genetics Keywords: RNA-Seq; Vitamin K; Comorbidities; Differential Expressed Genes; Variant analysis
Online: 23 September 2022 (09:13:29 CEST)
Systems genetics is key for integrating a large number of variants associated with diseases. Vitamin K (VK) is one of the scarcely studied conditions in lieu of ascertaining either the differentially expressed genes (DEGs) or variants in an individual subpopulation of diseased phenotypes associated with VK, viz. myocardial infarction, renal failure, prostate cancer, thrombosis, thrombocytopenia, coagulation related diseases to name a few. In this work, we have screened characteristic DEGs common to three VK-related diseases, viz. myocardial infarction, renal failure and prostate cancer and asked whether or not any DEGs in addition to pathogenic variants are common to these conditions. We attempt to bridge the gap in finding characteristic biomarkers and discuss the role of long noncoding RNAs (lncRNAs) in the biogenesis of VK deficiencies.
ARTICLE | doi:10.20944/preprints202205.0131.v1
Subject: Life Sciences, Virology Keywords: SARS-CoV-2; Variants of Concern; Delta Variant; genomic surveillance.
Online: 10 May 2022 (09:44:11 CEST)
In this study, we analyzed sequences of SARS-CoV-2 isolates of the Delta variant in Mexico, which completely replaced other previously circulating variants in the country due to its transmission advantage. Among Delta sublineages detected, 81.5 % were classified as AY.20, AY.26, and AY.100. According to publicly available data, these sublineages only reached a world prevalence of less than 1%, suggesting a possible Mexican origin. The signature mutations of these sublineages are described, and phylogenetic analyses and haplotype networks were used to track their spread across the country. Other frequently detected sublineages include AY.3, AY.62, AY.103, and AY.113. Over time, the principal sublineages showed different geographical distributions, with AY.20 predominant in Central Mexico, AY.26 in the North, and AY.100 in the Northwest and South/Southeast. This work describes the circulation, from May to November 2021, of the primary sublineages of the Delta variants associated to the third wave of the COVID-19 pandemic in Mexico and reinforces the importance of SARS-CoV-2 genomic surveillance for timely identification of emerging variants that may impact public health.
ARTICLE | doi:10.20944/preprints202204.0266.v1
Subject: Biology, Other Keywords: SARS CoV-2; Variant of Concern; Omicron; mutation; genomic surveillance
Online: 28 April 2022 (03:28:50 CEST)
Genomic surveillance represents an important strategy for understanding evolutionary mechanisms, transmission profile, and infectivity of different SARS-CoV-2 variants. We assessed the epidemiological profile of 366 individuals who tested positive for SARS-CoV-2 from 29 municipalities in Rondônia between December 2021 to March 2022. Samples were collected, RNA was ex-tracted and screened using RT-qPCR for Alpha, Beta, Gamma, Delta and Omicron VOCs and viral quantification was performed. Sequences were analyzed for phylogeny, mutations and lineages. Of the samples analyzed, 93.71% were positive for the Omicron variant and 6.28% were positive for the Delta variant. The symptoms observed were cough, sore throat, and fever, with a mean duration of 5 days; no hospitalizations or deaths were reported. We noted that among the positive individuals, 51% had been immunized with two doses, 22% received three doses, 13% received one dose, and 13% were not immunized. Just 242 samples were amenable to analysis for alignment and phylogenetic characterization; corresponding to variants BA.1 and BA.1.1; a total of 120 mutations were identified, 36% of which were found in the S gene. In conclusion, there was a high frequency of mutations in the SARS-CoV-2 genome, but no record of clinical severity, demonstrating the positive effect of vaccination.
ARTICLE | doi:10.20944/preprints202203.0194.v1
Subject: Life Sciences, Immunology Keywords: HLA; MHC class I; polymorphism; variant; type 2 diabetes; mexican
Online: 15 March 2022 (03:49:43 CET)
Type 2 diabetes has been linked to the expression of Human Leukocyte Antigens, principally to the major Histocompatibility Complex Class II and only scarce reports to Major Histocompatibility Complex class I in specific populations. The objective of the present work was to explore the presence of polymorphisms in the MHC class I related to Type 2 diabetes in the Mexican population using the GWAS SIGMA database. This database contains information of 3,848 Mexican individuals with type 2 diabetes and 4,366 control individuals from the same population without clinical or hereditary history of the disease. The searching criteria considered a P value < 0.005 and odds ratio, OR > 1.0. Ten novel statistically significant nucleotide variants were identified: four polymorphisms associated with HLA-A (A*03:01:01:01), and six with HLA-C (C*01:02:01:01). These alleles have a high prevalence in Latin American populations and could potentially be associated with autoimmunity mechanisms related with the development of Type 2 diabetes complications.
ARTICLE | doi:10.20944/preprints202203.0155.v1
Subject: Life Sciences, Virology Keywords: SARS-CoV-2; Omicron variant; Monoclonal antibody; Neutralization; Spike protein
Online: 10 March 2022 (14:30:25 CET)
SARS-CoV-2 Omicron variants contain many mutations in its spike receptor binding domain, the target of all authorized monoclonal antibodies (mAbs). Determining the extent to which Omicron variants reduced mAb susceptibility is critical to preventing and treating COVID-19. We systematically reviewed PubMed and three preprint servers, last updated February 22, 2022, of the in vitro activity of authorized mAbs against the Omicron variants. Thirty-three studies were eligible including 33 containing Omicron BA.1 susceptibility data and five that also contained Omicron BA.2 susceptibility data. The first two authorized mAb combinations, bamlanivimab/etesevimab and casirivimab/imdevimab, were inactive against the Omicron BA.1 and BA.2 variants. In 24 studies, sotrovimab (third authorized mAb) displayed a median 4.1-fold (IQR: 2.4-7.6) reduced activity against Omicron BA.1 and, in four studies, a median 26-fold (IQR:16-35) reduced activity against Omicron BA.2. In 18 studies, cilgavimab and tixagevimab independently displayed median reductions in activity of >300-fold against Omicron BA.1, while in ten studies, the cilgavimab/tixagevimab combination (fourth authorized mAb preparation) displayed a median 63-fold (IQR: 26-145) reduced activity against Omicron BA.1. In two studies, cilgavimab was approximately 100-fold more susceptible to BA.2 than to BA.1. In two studies, bebtelovimab, the most recently authorized mAb, was fully active against both the Omicron variants. Disparate results between assays were common as evidenced by a median 42-fold range (IQR: 25-625) in IC50 between assays for the eight authorized individual mAbs and three authorized mAb combinations. Highly disparate results between published assays indicates a need for improved mAb susceptibility test standardization or inter-assay calibration.
Subject: Life Sciences, Virology Keywords: ACE2; Spike protein; SARS-CoV2; death rate; polymorphism; isoform variant; CD157, sankramikogenomics
Online: 17 May 2020 (14:51:39 CEST)
The 2019-Novel Coronavirus has currently gripped the world in terror, affecting 210 countries and territories. Originating from Wuhan, Hubei province, China, the virus has spread so rapidly throughout the world and has already claimed 308,927 lives and is currently afflicting 4.6 million people. The US has over 1.48 million confirmed cases of COVID-19, followed by Spain, Italy, France, UK, Germany, Turkey, Russia, Iran, and China. On careful inspection of the COVID-19 statistics, a peculiar unsettling trend becomes apparent. Western European countries and the US appear to have difficulties in overcoming the catastrophe. In contrast, countries in East Asia, Middle East and mid-Europe have sorted out the situation. Here, we will highlight this trend and propose the importance of infection-genomics (sankramikogenomics), in understanding the susceptibility to COVID-19 and the severity of disease progress. More detailed, systematic evaluation may also identify more susceptible populations. We will also highlight mere 12-fold lower affinity is insufficient to ignore CD147, as interactions occur between tens of spike proteins and equal number of cell surface ACE2 and/or CD147. Thus, both receptors are important to understand sankramikogenomics and severity of COVID-19. The observed ethnic differences in COVID severities may be due to variations in structure or tissue-specific expression (alternate splicing and accessibility) of both the target receptors. Research on both receptors may help in designing improved therapeutic strategies to fight COVID-19. Similar to pharmacogenomics to drug development and precision medicine, Sankramikogenomics will become an important field in other infectious diseases and pathogenicity.
ARTICLE | doi:10.20944/preprints201811.0280.v1
Subject: Life Sciences, Genetics Keywords: HSP47; missense mutation; mutational hotspot; variant analysis; cancer database; chaperone
Online: 12 November 2018 (10:23:29 CET)
Heat shock protein 47kDa (HSP47) serves as a client-specific chaperone, essential for collagen biosynthesis and its folding and structural assembly. To date, there is no comprehensive study on mutational hotspots and protein network for human HSP47. Using five different human mutational databases, we deduced a comprehensive list of human HSP47 mutations and we found 24 67, 50, 43 and 2 deleterious mutations from the 1000 genomes data, gnomAD, COSMICv86, cBioPortal, and CanVar. We identified thirteen top-ranked missense mutations of HSP47 with the stringent cut-off of CADD score (>25) and Grantham score (≥151) as Ser76Trp, Arg103Cys, Arg116Cys, Ser159Phe, Arg167Cys, Arg280Cys, Trp293Cys, Gly323Trp, Arg339Cys, Arg373Cys, Arg377Cys, Ser399Phe, and Arg405Cys with the arginine-cysteine change as the predominant mutation. We also found that HSP47 is up-regulated and down-regulated in 11 and 4 of cancers types. Upon constructing protein interactome map of human HSP47, we found that a set of molecular chaperones is interaction partners of HSP47, which included two copies each of CREB binding proteins, HSP27, HSP40, HSP70, HSP90, ubiquitin proteins and one copy each of cartilage associated protein (CRTAP), HSPH1, HSBP1, FK506-binding protein B (FKBP), kruppel-like factor (KLF13), peptidyl-prolyl isomerase PIPB and Prolyl 4-hydroxylase beta subunit (P4HB). This suggested a cocktail of different chaperones interact with HSP47. These findings will assist in the evaluation of roles of HSP47 in human disease including different types of cancers.
ARTICLE | doi:10.20944/preprints202101.0330.v1
Subject: Medicine & Pharmacology, Allergology Keywords: germline; rare variant; cancer; lymphoid; B-cell; lymphomal; CLL; driver; prognosis
Online: 18 January 2021 (12:14:32 CET)
Growing evidence has revealed the implication of germline variation in cancer predisposition and prognostication. Here, we describe an analysis of putatively disruptive rare variants across the genomes of 726 patients with B-cell lymphoid neoplasms. We discovered a significant enrichment of 26 genes in germline protein truncating variants (PTVs), affecting cell signaling (MET, JAK2, ANGPT2), energy metabolism (ACO1) and nucleic acid metabolism and repair pathways (NT5E, DCK). Interestingly, some of these variants were restricted to either chronic lymphocytic leukemia (CLL) (i.e., ANGPT2 and AKR1C3) or B-cell lymphoma cases (PNMT, TPT1 and IGHMBP2). Additionally, we detected 1,675 likely disrupting variants in genes associated with cancer, of which 44.75% were novel events and 7.88% were PTVs. Among these, the most frequently affected genes were ATM, BIRC6, CLTCL1A and TSC2. Homozygous or compound heterozygous variants were detected in 28 cases; and coexisting somatic events were observed in 17 patients, some of which affected key lymphoma drivers such as ATM, KMT2D and MYC. Finally, we observed that variants in the helicase gene WRN were independently associated with shorter survival in CLL. Our study results support an important role for rare germline variation in the pathogenesis, clinical presentation and disease outcome of B-cell lymphoid neoplasms.
ARTICLE | doi:10.20944/preprints202206.0255.v1
Subject: Life Sciences, Immunology Keywords: coronaviruses; SARS-CoV-2; variant; Omicron; SLiMs; spike protein; motifs; covid-19
Online: 17 June 2022 (13:49:02 CEST)
Short Linear Motifs (SLiMs) are short linear sequences that can mediate protein-protein interaction. Mimicking eukaryotic SLiMs to compete with extra or intracellular binding partners or to sequester host proteins is the crucial strategy of viruses to pervert the host system. The evolved proteins in viruses facilitate minimal protein-protein interactions that significantly affect intracellular signaling networks. Unfortunately, very little information about the SARS-CoV-2 SLiMs is known, especially across the SARS-CoV-2 variants. Through ELM database-based sequence analysis of spike protein from all the major SARS-CoV-2 variants, we identified four overriding SLiMs in the SARS-CoV-2 Omicron variant including LIG_TRFH_1, LIG_REV1ctd_RIR_1, LIG_CaM_NSCaTE_8, and MOD_LATS_1. These SLiMs are highly likely to interfere with various immune functions, interact with host intracellular proteins, regulate cellular pathways, and lubricate viral infection and transmission. These cellular interactions possibly serve as potential therapeutic targets for these variants, and this approach can be further exploited to combat emerging SARS-CoV-2 variants.
ARTICLE | doi:10.20944/preprints202205.0292.v1
Subject: Life Sciences, Genetics Keywords: Meier-Gorlin syndrome; Jeune syndrome; ORC6; exon skipping variant; prenatal genetic testing
Online: 23 May 2022 (10:18:24 CEST)
Meier–Gorlin syndrome (MGS) is a rare genetic developmental disorder that causes primordial proportional dwarfism, microtia, absent or hypoplastic patellae and other skeletal anomalies. Overlapping skeletal symptoms make MGS difficult to diagnose clinically. We describe a 3-year-old boy with short stature, recurrent respiratory infections, short-rib dysplasia, tower head and facial dysmorphisms who was admitted to the Tomsk Genetic Clinic to verify a clinical diagnosis of Jeune syndrome. Clinical Exome sequencing revealed two variants (compound heterozygosity) in the ORC6 gene: c.2T>C(p.Met1Thr) and c.449+5G>A. In silico analysis showed the pathogenicity of these two mutations and predicted a decrease in donor splicing site strength for c.449+5G>A. An in vitro minigene assay demonstrated that variant c.449+5G>A causes a complete skipping of exon 4 in ORC6 gene. The parents asked for urgent prenatal testing for MGS for the next pregnancy, but it ended in a miscarriage. Thus, this case report may help to prevent MGS misdiagnosis in the future. We also performed in silico and functional analyses of ORC6 mutations and developed a restriction fragment length polymorphism and haplotype-based short-tandem-repeat assay for prenatal genetic testing for MGS. These findings should elucidate MGS aetiology and improve the quality of genetic counselling for affected families.
ARTICLE | doi:10.20944/preprints202112.0473.v1
Subject: Medicine & Pharmacology, Other Keywords: Fanconi anemia; Chromosome instability; FANCG; splicing; founder pathogenic variant; Mixe indigenous group.
Online: 29 December 2021 (19:28:49 CET)
Fanconi anemia (FA) is a rare genetic disorder caused by pathogenic variants (PV) in at least 22 genes, which cooperate in the FA/BRCA pathway to maintain genome stability. PV in FANCA, FANCC, and FANCG account for most cases (~90%). This study evaluated the chromosomal, molecular, and phenotypic findings of a novel founder FANCG PV, identified in three patients with FA from the Mixe community of Oaxaca, Mexico. All patients presented chromosomal instability and a homozygous PV, FANCG: c.511-3_511-2delCA, identified by next-generation sequencing analysis. Bioinformatics predictions suggest that this deletion disrupts a splice acceptor site promoting the exon 5 skipping. Analysis of Cytoscan 750K arrays for haplotyping and global ancestry supported the Mexican origin and founder effect of the variant, reaffirming the high frequency of founder PV in FANCG. The degree of bone marrow failure and physical findings (described through the acronyms VACTERL-H and PHENOS) were used to depict the phenotype of the patients. Despite having a similar frequency of chromosomal aberrations and genetic constitution, the phenotype showed a wide spectrum of severity. The identification of a founder PV could help for a systematic and accurate genetic screening of patients with FA suspicion in this population.
ARTICLE | doi:10.20944/preprints202005.0396.v1
Subject: Life Sciences, Virology Keywords: SARS-CoV-2; COVID-19; coronavirus; variant analysis; phylogenetic analysis; viral evolution
Online: 24 May 2020 (18:25:47 CEST)
The severe acute respiratory syndrome-coronavirus 2 (SARS-CoV-2) viral genome is an RNA virus consisting of approximately 30,000 bases. As part of testing efforts, whole genome sequencing of human isolates has resulted in over 1,600 complete genomes publicly available from GenBank. We have performed a comparative phylogenetic analysis of the sequences, in order to detect common mutations within the population. Analysis of variants occurring within the assembled genomes yields 417 variants occurring in at least 1% of the completed genomes, including 229 within the 5’ untranslated region (UTR), 152 within the 3’UTR, 2 within intergenic regions and 34 within coding sequences.
COMMUNICATION | doi:10.20944/preprints201909.0346.v1
Subject: Life Sciences, Genetics Keywords: neurogenetics; dementia; next-generation sequencing; in silico analysis; genetic variant; phenotypic variability
Online: 30 September 2019 (11:05:36 CEST)
Background: Advancements in the next-generation sequencing (NGS) techniques have allowed for efficient genetic variant detection at reduced costs. Methods: We describe an ad hoc NGS-based custom designed resequencing gene panel to identify genetic variants in 8 patients with dementing disorders. Results: We found variants of TREM2 and APP genes in three patients; these have been previously identified as pathogenic or likely pathogenic and, therefore, considered as “Disease Causing”. In the remaining subjects, the pathogenicity was evaluated on the in silico analysis, according to the guidelines of the American College of Medical Genetics. In one patient, the p.R205W variant was causative of the disease, thus considered as “Possibly Disease Causing”. The variants found from the other four subjects in the CSF1R, SERPINI1, GRN, and APP genes revealed discordant in silico results and, therefore, it was not possible to assign a definitive pathogenicity. Conclusions: Notwithstanding the limitations of a customized panel, we detected some rare genetic variants with a probable disease association. The future application of NGS techniques and the further replication of these experimental data will replace the so-called “gene by gene” approach with a “panel of genes” strategy, that offers promising perspectives in the diagnosis and management of neurodegenerative disorders.
ARTICLE | doi:10.20944/preprints202209.0318.v1
Subject: Life Sciences, Virology Keywords: BA.2.75 variant; Gibbs energy of binding; binding rate; infectivity; SARS-CoV-2
Online: 21 September 2022 (09:44:34 CEST)
Omicron BA.2.75 may become the next globally dominant strain of COVID-19 in 2022. BA.2.75 sub-variant has acquired more mutations (9) in spike protein and other genes of SARS-CoV-2 than any other variant. Thus, its chemical composition and thermodynamic properties have changed comparing to earlier variants. In this paper Gibbs energy of binding and antigen-receptor binding rate is reported for the BA.2.75 variant. Gibbs energy of binding (driving force of binding) of Omicron BA.2.75 variant is more negative than that of the competing variants BA.2 and BA.5.
ARTICLE | doi:10.20944/preprints202201.0466.v1
Subject: Medicine & Pharmacology, Ophthalmology Keywords: FOXC1; in vitro studies; novel variant; ophthalmic genetics; intrafamilial variability; anterior segment dysgenesis
Online: 31 January 2022 (13:36:18 CET)
Anterior segment dysgenesis (ASD) encompasses a wide spectrum of developmental abnormalities of the anterior ocular segment, including congenital cataract, iris hypoplasia, aniridia, iridocorneal synechiae, as well as Peters, Axenfeld, and Rieger anomalies. Here, we report a large five-generation Caucasian family exhibiting atypical syndromic ASD segregating with a novel truncating variant of FOXC1. The family history is consistent with highly variable autosomal dominant symptoms including isolated glaucoma, iris hypoplasia, aniridia, cataract, hypothyroidism, congenital heart anomalies, and cystic kidney disease. Whole exome sequencing revealed a novel variant [c.313_314insA; p.(Tyr105*)] in FOXC1 that disrupts the alpha-helical region of the DNA-binding forkhead box domain. In vitro studies using a heterologous cell system revealed aberrant cytoplasmic localization of FOXC1 harboring the Tyr105* variant, likely precluding downstream transcription function. Meta-analysis of the literature highlighted the intrafamilial variability related to FOXC1 truncating alleles. This study highlights the clinical variability in ASD and signifies the importance of combining both clinical and molecular analysis approaches to establish a complete diagnosis.
ARTICLE | doi:10.20944/preprints202206.0272.v1
Subject: Medicine & Pharmacology, Other Keywords: COVID-19; SARS-CoV-2; molnupiravir; nirmatrelvir; GC376; PF-07321332; variant; synergy; an-tiviral
Online: 20 June 2022 (10:57:26 CEST)
Introduction: The development of effective vaccines has partially mitigated the trend of the SARS-CoV-2 pandemic, however, the need for orally available antiviral drugs persists. This study aims to investigate the activity of molnupiravir in combination with nirmatrelvir or GC376 on SARS-CoV-2 to verify the synergistic effect. Methods: The SARS-CoV-2 strains 20A.EU, BA.1 and BA.2 were used to infect Vero E6 in presence of antiviral compounds alone or in combinations using 5 two-fold serial dilution of compound concentrations ≤EC90. After 48 and 72 h post-infection, viability was performed using MTT reduction assay. Supernatants were collected for plaque-assay titration. All experiments were conducted three times and in triplicate. The synergistic score was calculated using Synergy Finder version 2. Results: All compounds reached micromolar EC90. Molnupiravir and GC376 showed a synergistic activity at 48 h with an HSA score of 19.33 (p<0.0001) and an additive activity at 72 h with an HSA score of 8.61 (p<0.0001). Molnupiravir and nirmatrelvir showed a synergistic activity both at 48 h and 72 h with an HSA score of 14.2 (p=0.01) and 13.08 (p<0.0001), respectively. Conclusion: Molnupiravir associated with one of the two protease-inhibitors nirmatrelvir and GC376 showed good additive-synergic activity in vitro.
CASE REPORT | doi:10.20944/preprints202204.0285.v1
Subject: Medicine & Pharmacology, Pediatrics Keywords: GLDN variant; gliomedin; juvenile progressive respiratory insufficiency; diaphragmatic hypomotility; scoliosis; arthrogryposis; LCCS11; axonopathy; FADS
Online: 29 April 2022 (03:36:40 CEST)
Lethal congenital contracture syndrome 11 (LCCS11) is a form of arthrogryposis multiplex congenita (AMC) which is associated with mutations in the gliomedin gene (GLDN) and has been known to be severely life-shortening, mainly due to respiratory insufficiency. Patients with this condition have been predominantly treated by pediatricians as they usually do not survive beyond childhood. In this case report we present a young adult who developed severe progressive respiratory insufficiency as a teenager due to diaphragmatic hypomotility and was diagnosed with LCCS11 following the finding of compound heterozygous pathogenic variants in GLDN. This case demonstrates the importance of screening for neuromuscular diseases in well-child visits and follow-ups of patients at risk for gross and fine motor function developmental delay. It also underscores the significance of including LCCS11 and other axonopathies in the differential diagnosis of juvenile onset of respiratory insufficiency, highlights that patients with this condition may present to adult practitioners and questions whether the nomenclature of this condition with various phenotypes should be reconsidered due to the stigmatizing term ‘lethal’.
COMMUNICATION | doi:10.20944/preprints202203.0185.v1
Subject: Medicine & Pharmacology, Other Keywords: SARS-CoV-2; COVID-19; variant; sublineage; transmission; immunity; infection; vaccination; non-pharmaceutical interventions
Online: 14 March 2022 (11:19:04 CET)
The scientific, private and industrial sectors use a wide variety of technological platforms available to achieve protection against SARS-CoV-2, including vaccines. However, the virus evolves continually into new highly virulent variants, which might overcome the protection provided by vaccines and may re-expose the population to infections. Mass vaccinations should be continued in combination with more or less obligation mandatory non-pharmaceutical interventions. Therefore, the key questions to be answered are: (i) How to identify the primary and secondary infections of SARS-CoV-2? (ii) Why are neutralizing antibodies not long-lasting in both the cases of natural infections and post-vaccinations? (iii) Which are the factors responsible for this decay in neutralizing antibodies? (iv) What strategy could be adapted to develop long-term herd immunity? (v) Is the Spike the only vaccine candidate or a vaccine cocktail is better?
CASE REPORT | doi:10.20944/preprints202202.0251.v1
Subject: Medicine & Pharmacology, Cardiology Keywords: Infective endocarditis; Granulicatela adiacens; Nutritionally variant streptococci (NVS); Next-generation sequencing (NGS); Aortic valve
Online: 21 February 2022 (10:45:14 CET)
In this report, we describe the course and successful treatment of complicated infective endocarditis (IE). A patient presented with a high-grade irregular fever with chills lasting at least 2 months, dyspnoea, chest pain, fatigue, weight loss, and night sweats during the previous 3 months. Above cardiac congenital disorders, he was found to have Granulicatella adiacens infective aortic valve endocarditis, presumably transmitted from the oral cavity niche. Validated metagenomic 16S rDNA next generation sequencing was used to perform taxonomic identification, allowing for specific adequate antibiotic therapy instead of empiric therapy. This paper highlights the critical role of rapid taxonomic identification of nutritionally variant streptococci crucial and the benefit of proper IE treatment to avoid relapses or fatal complications.
REVIEW | doi:10.20944/preprints202202.0224.v1
Subject: Life Sciences, Virology Keywords: COVID-19; pandemic; SARS-CoV-2; Omicron variant; emerging disease; global health; virus; genome; mutation
Online: 18 February 2022 (05:23:18 CET)
The 2019 Coronavirus Disease (COVID-19) is a major cause of morbidity and mortality worldwide. Since late November 2021, Omicron variant has emerged as the primary cause of COVID-19 and caused a huge increase in the reported incidence around the world. To date, 32-34 spike mutations have been reported, 15 of which were located in the receptor-binding domain that interacts with the cell surface of the host cells, while the rest were located in the N-terminal domain and around the Furin cleavage site. At present, both the genomic and clinical profiles of this novel variant are being investigated. Here, we aim to discuss the recent reports on the transmissibility and severity of Omicron variant from both the genetic and clinical perspectives. Afterward, we also take the chance to deliver our personal view on the topic.
ARTICLE | doi:10.20944/preprints201911.0271.v1
Subject: Life Sciences, Genetics Keywords: breast cancer risk; GWAS; candidate causal variant; chromatin conformation capture; reporter gene activity; enhancer; promoter
Online: 24 November 2019 (05:12:07 CET)
Genome-wide association studies have revealed a locus at 8p12 that is associated with breast cancer risk. Fine-mapping of this locus identified 16 candidate causal variants (CCVs). However, as these variants are intergenic, their function is unclear. To map chromatin looping from this risk locus to a previously identified candidate target gene, DUSP4, we performed chromatin conformation capture analyses in normal and tumoral breast cell lines. We identified putative regulatory elements, containing CCVs, that loop to the DUSP4 promoter region. Using reporter gene assays, we found that the risk allele of CCV rs7461885 reduced the activity of a DUSP4 enhancer element, consistent with the function of DUSP4 as a tumor suppressor gene. Furthermore, the risk allele of CCV rs12155535, located in another DUSP4 enhancer element, was negatively correlated with looping of this element to the DUSP4 promoter region, suggesting that this allele would be associated with reduced expression. These findings provide the first evidence that CCV risk alleles downregulate DUSP4 expression, suggesting that this gene is a regulatory target of the 8p12 breast cancer risk locus.
Subject: Life Sciences, Virology Keywords: foot-and-mouth disease virus; vaccine efficacy; serotype O/ME-SA/Ind2001 variant; heterologous challenge; cattle
Online: 23 August 2021 (14:17:25 CEST)
Vaccination is one of the best approaches to control and eradicate foot-and-mouth disease (FMD). To achieve this goal, vaccines with inactivated FMD virus antigen in suitable adjuvants are being used in addition with other control measures. However, only a limited number of vaccine strains are commercially available which often have a restricted spectrum of activity against the different FMD virus strains in circulation. As a result, when new strains emerge, it is important to measure the efficacy of the current vaccine strains against these new variants. This is important for countries where FMD is endemic but also for countries that hold an FMD vaccine bank to be prepared for emergency vaccination. The emergence and spread of the O/ME-SA/Ind-2001 lineage of viruses posed a serious threat to countries which had OIE-endorsed FMD control plans and had not reported FMD for many years. In vitro vaccine matching results showed a poor match (r1-value <0.3) to the more widely used vaccine strain O Manisa and less protection in a challenge test. This paper describes the use of O3039 vaccine strain as an alternative either alone or in combination with the O Manisa vaccine strain with virulent challenge by a O/ME-SA/Ind-2001d sub-lineage virus from Algeria (O/ALG/3/2014). The experiment included challenge at 7 days post vaccination (to study protection and emergency use) and 21 days post vaccination (as would be done in standard potency studies). The results indicated that the O3039 vaccine strain alone as well as the combination with O Manisa is effective against this strain of the O/ME-SA/Ind/2001d lineage offering protection from clinical disease even after 7 days post vaccination and with reduction in viraemia and virus excretion.
ARTICLE | doi:10.20944/preprints202008.0206.v1
Subject: Life Sciences, Microbiology Keywords: tongue microbiome; salivary microbiome; amplicon sequence variant (ASV); operational taxonomical unit (OTU); denoising; DADA2; taxonomic classifier
Online: 8 August 2020 (09:29:46 CEST)
The bacterial composition of oral samples has traditionally been determined by PCR amplicon sequencing of 16S rRNA genes. Recent amplicon sequence variant (ASV)-based analyses of 16S rRNA genes differ from that based on operational taxonomic unit (OTU) clustering in the way it deals with sequences having potential errors. However, little information is available on its application in oral microbiome studies. Here, we conducted ASV-based analysis of oral microbiome samples using QIIME 2. We investigated the optimal parameters for sequence denoising, using DADA2, and found the trimming of the first 20 nucleotides from 5′-end of both paired reads avoided excessive sequence loss during chimera removal. Truncating reads at positions 240–245 allowed the removal of low-quality sequences while maintaining sufficient length to merge matching paired ends. Taxonomic assignment, using the naïve Bayes classifier trained with the V3-V4 region of reference 16S rRNA sequences in the extended human oral microbiome database (eHOMD), resulted in bacterial compositions similar to those of OTU-based analyses. Contrary to OTU-based clustering, ASV-based analysis showed taxonomic abundance at the genus or species level to not differ significantly in tongue microbiomes, regardless of brushing. QIIME 2 can, therefore, be a standard pipeline for ASV-based analysis of oral microbiomes.
BRIEF REPORT | doi:10.20944/preprints202004.0024.v1
Subject: Life Sciences, Virology Keywords: COVID-19; SARS-nCoV-2; vaccine; antibody; immune escape; variant; spike protein; genomic drift; convalescent plasma
Online: 3 April 2020 (04:24:52 CEST)
New coronavirus (SARS-CoV-2) treatments and vaccines are under development to combat the COVID-19 disease. Several approaches are being used by scientists for investigation including 1) various small molecule approaches targeting RNA polymerase, 3C-like protease, and RNA endonuclease and 2) exploration of antibodies obtained from convalescent plasma from patients who have recovered from COVID-19. The coronavirus genome is highly prone to mutations that lead to genetic drift and escape from immune recognition; thus, it is imperative that sub-strains with different mutations are also accounted for during vaccine development. As the disease has grown to become a pandemic, new B-cell and T-cell epitopes predicted from SARS coronavirus have been reported. Using the epitope information along with variants of the virus, we have found several variants which might cause drifts. Among such variants, 23403A>G variant (p.D614G) in spike protein B-cell epitope is observed frequently in European countries such as the Netherlands, Switzerland and France.
CONCEPT PAPER | doi:10.20944/preprints202207.0408.v1
Subject: Life Sciences, Genetics Keywords: Lynch syndrome variant heterozygotes; colorectal and non-colorectal cancers; frameshift muta-tions; neoantigens; immune responses; immunogenomic biomarkers
Online: 26 July 2022 (10:58:51 CEST)
Lynch syndrome (LS) is an inherited disorder in which affected individuals have a significantly higher-than-average risk of developing colorectal and non-colorectal cancers, often before the age of 50 years. In LS, mutations in DNA repair genes lead to a dysfunctional post-replication repair system. As a result, the unrepaired errors in coding regions of the genome produce novel proteins, called neoantigens. Neoantigens are recognised by the immune system as foreign and trigger an immune response. Due to the invasive nature of cancer screening tests, universal cancer screening guidelines unique for LS (including colonoscopy) are poorly adhered to by LS variant heterozygotes (LSVH). Currently, it is unclear whether immunogenomic components produced as a result of neoantigen formation can be used as novel biomarkers in LS. We hypothesize that: (i) LSVH produce measurable and dynamic immunogenomic components in blood, and (ii) these quantifiable immunogenomic components correlate with cancer onset and stage. Here, we discuss feasibility and propose the potential to: (a) identify personalised novel immunogenomic biomarkers, (b) reduce invasive cancer screening tests and thus increase non-invasive cancer surveillance, (c) improve compliance and adherence to recommended cancer screening guidelines in LSVH.
ARTICLE | doi:10.20944/preprints201811.0183.v2
Subject: Life Sciences, Molecular Biology Keywords: sequencing technologies; NGS; genome research; genome assembly; variant calling; RNA-Seq; transcriptome assembly; bioinformatics; molecular biology; education
Online: 13 November 2018 (10:22:06 CET)
Combined awareness about the power and limitations of bioinformatics and molecular biology enables advanced research based on high-throughput data. Despite an increasing demand for scientists with a combined background in both fields, the education in dry lab and wet lab is often separated. This work describes an example of integrated education with focus on genomics and transcriptomics. Participants learn computational and molecular biology methods in the same practical course. Peer-review is applied as a teaching method to foster cooperative learning of students with heterogeneous backgrounds. Evaluation results indicate acceptance and appreciation of this approach.
ARTICLE | doi:10.20944/preprints202207.0286.v1
Subject: Life Sciences, Microbiology Keywords: SARS-CoV-2; Omicron variant of concern; homologous boosting; heterologous boosting; Coro-naVac; BNT162b2; healthcare worker; return-to-work
Online: 19 July 2022 (10:15:39 CEST)
Immune escape is observed with SARS-CoV-2 Omicron (Pango lineage B.1.1.529), the predominant circulating strain worldwide. Booster dose was shown to restore immunity against Omicron infection, however, real world data comparing mRNA (BNT162b2; Comirnaty) and inactivated vaccine (CoronaVac; Sinovac) homologous and heterologous boosting is lacking. A retrospective study was performed to compare the rate and outcome of COVID-19 in healthcare workers (HCWs) with various vaccination regime during a territory-wide Omicron outbreak in Hong Kong. During the study period 1 Feb – 31 Mar 2022, 3167 HCWs were recruited, 871 HCWs reported 746 and 183 episodes of significant household and non-household close contact. 737 HCWs acquired COVID-19 which were all clinically mild. Time dependent Cox regression showed that, comparing with 2-dose vaccination, 3-dose vaccination reduced infection risk by 31.7% and 89.3% in household contact and non-household close contact respectively. Using 2-dose BNT162b2 as reference, 2-dose CoronaVac recipient had significantly higher risk of being infected (HR 1.69 P<0.0001). Three-dose BNT162b2 (HR 0.4778 P<0.0001) and 2-dose CoronaVac + BNT162b2 booster (HR 0.4862 P=0.0157) were associated with lower risk of infection. Three-dose CoronaVac and 2-dose BNT162b2 + CoronaVac booster were not significantly different from 2-dose BNT162b2. The mean time to achieve negative RT-PCR or E gene cycle threshold 31 or above was not affected by age, number of vaccine dose taken, vaccine type and timing of the last dose. In summary, we have demonstrated lower risk of breakthrough SARS-CoV-2 infection in HCWs given BNT162b2 as booster after 2 doses of BNT162b2 or CoronaVac.
ARTICLE | doi:10.20944/preprints202206.0192.v1
Subject: Medicine & Pharmacology, General Medical Research Keywords: eCDC; WHO; Sanger sequencing; Omicron variant; minor subvariants; BA.4/BA.5; BA.2; mul-ti-allelic; SNPs; recombinant
Online: 14 June 2022 (04:30:41 CEST)
Large population passages of the SARS-CoV-2 in the past two and a half years have allowed the circulating virus to accumulate an increasing number of mutations in its genome. The most recently emerging Omicron subvariants have the highest number of mutations in the Spike (S) protein gene and these mutations mainly occur in the receptor-binding domain (RBD) and the N-terminal domain (NTD) of the S gene. The eCDC and the WHO recommend partial Sanger sequencing of the SARS-CoV-2 S gene RBD and NTD on the PCR-positive samples in diagnostic laboratories as a practical means of determining the variants of concern to monitor a possible increased transmissibility, increased virulence, or reduced effectiveness of vaccines against them. The author’s diagnostic laboratory has implemented the eCDC/WHO recommendation by sequencing a 398-base segment of the N gene for the definitive detection of SARS-CoV-2 in clinical samples, and sequencing a 445-base segment of the RBD and a 490-509-base segment of the NTD for variant determination. This paper presents 5 selective cases to illustrate the challenges of using Sanger sequencing to diagnose Omicron subvariant when the samples harbor a high level of co-existing minor subvariant sequences with multi-allelic single nucleotide polymorphisms (SNPs) or possible recombinant Omicron subvariants containing a BA.1 NTD and a BA.2 RBD, which can only be detected by using specially designed PCR primers. The current large-scale surveillance programs using next-generation sequencing (NGS) do not face similar problems because NGS focuses on deriving consensus sequence.
REVIEW | doi:10.20944/preprints201902.0090.v1
Subject: Life Sciences, Genetics Keywords: BRCA1; variants of uncertain clinical significance; VUS; germline variants; hereditary breast and ovarian cancer; breast cancer; genetic testing, ovarian cancer; variant classification; clinical annotation
Online: 11 February 2019 (16:12:03 CET)
Genetic testing allows for identification of germline DNA variations which are associated with a significant increase in risk of developing breast and ovarian cancer. Detection of a BRCA1 or BRCA2 pathogenic variant triggers several clinical management actions, which may include increased surveillance and prophylactic surgery for healthy carriers or treatment with PARP inhibitor therapy for carriers diagnosed with cancer. Thus, standardized validated criteria for annotation of BRCA1 and BRCA2 variants according to their pathogenicity are necessary to support clinical decision making and ensure improved outcomes. Upon detection, variants whose pathogenicity can be inferred by the genetic code are typically classified as pathogenic, likely pathogenic, likely benign, or benign. Variants whose impact on function cannot be directly inferred by the genetic code are labeled as Variants of Uncertain Clinical Significance (VUS) and are evaluated by multifactorial likelihood models that use personal and family history of cancer, segregation data, prediction tools, and co-occurrence with a pathogenic BRCA variant. Missense variants, coding alterations that replace a single amino acid residue with another, are a class of variants for which determination of clinical relevance is particularly challenging. Here, we discuss current issues in variant classification by following a typical life cycle of a BRCA1 missense variant through detection, annotation and information dissemination. Advances in massively parallel sequencing have led to a substantial increase in VUS findings. Although comprehensive assessment and classification of missense variants according to their pathogenicity remains the bottle neck, new developments in functional analysis, high throughput assays, data sharing, and statistical models are rapidly changing this scenario.
COMMUNICATION | doi:10.20944/preprints202106.0091.v1
Subject: Life Sciences, Biochemistry Keywords: COVID-19; SARS-CoV-2 variant; lateral flow immunoassay; spike protein; receptor binding domain (RBD); neutralizing antibody; therapeutic antibody cocktail; epitope binning; rapid neutralization test; ACE2
Online: 2 June 2021 (16:11:29 CEST)
Identifying anti-spike antibodies that exhibit strong neutralizing activity against current dominant circulating variants and antibodies that are escaped by these variants have important implications in the development of therapeutic and diagnostic solutions as well as in improving understanding of the humoral response to SARS-CoV-2 infection. We characterized seven anti-RBD monoclonal antibodies for their binding activity, pairing capability and neutralization activity to SARS-CoV-2 and three variant RBDs (UK, SA and BR P.1) via lateral flow immunoassays. The results allowed us to group these antibodies into three distinct epitope bins. Our studies showed that two antibodies had broadly potent neutralizing activity against SARS-CoV-2 and these variant RBDs and that one antibody did not neutralize the SA and BR P.1 RBDs. The antibody escaped by the SA and BR P.1 RBDs retained binding activity to SA and BR P.1 RBDs but was unable to induce neutralization. Further, we demonstrated that the lateral flow immunoassay can be a rapid and effective tool for antibody characterization, including epitope classification and antibody neutralization kinetics. From these studies, the potential contributions of the mutations (N501Y, E484K and K417N/T) contained in these variants’ RBDs on antibody pairing capability, neutralization activity and therapeutic antibody targeting strategy are discussed.
ARTICLE | doi:10.20944/preprints202109.0415.v2
Subject: Life Sciences, Virology Keywords: Delta variant; Variants of concern; Variants of interest; SARS-CoV-2; Spike protein; Nested RT-PCR; Sanger sequencing; Amino acid mutations; ACE2 RBD; N-terminal domain (NTD)
Online: 2 November 2021 (10:40:46 CET)
As SARS-CoV-2 continues to spread among human populations, genetic changes occur and accumulate in the circulating virus. Some of these genetic changes have caused amino acid mutations, including deletions, which may have potential impact on critical SARS-CoV-2 countermeasures, including vaccines, therapeutics, and diagnostics. Considerable efforts have been made to categorize the amino acid mutations of the angiotensin-converting enzyme 2 (ACE2) receptor binding domain (RBD) of the spike (S) protein along with certain mutations in other regions within the S protein as specific variants in an attempt to study the relationship between these mutations and the biological behavior of the virus. However, the currently used whole genome sequencing surveillance technologies can test only a small fraction of the positive specimens with high viral loads and often generate uncertainties in nucleic acid sequencing that needs additional verification for precision determination of mutations. This article introduces a generic protocol to routinely sequence a 437-bp nested RT-PCR cDNA amplicon of the ACE2 RBD and a 490-bp nested RT-PCR cDNA amplicon of the N-terminal domain (NTD) of the S gene for detection of the amino acid mutations needed for accurate determination of all variants of concern and variants of interest according to the definitions published by the U.S. Centers for Disease Control and Prevention. This protocol was able to amplify both nucleic acid targets into cDNA amplicons to be used as templates for Sanger sequencing on all 16 clinical specimens that were positive for SARS-CoV-2.