ARTICLE | doi:10.20944/preprints202202.0330.v1
Online: 25 February 2022 (09:36:05 CET)
The genetic aetiology of familial glioma is largely unknown. To gain further insight into the role of rare disruptive variants we performed whole exome sequencing (WES) of 17 glioma families, identifying two families where loss of function mutations in dynein axonemal heavy chain 11 (DNAH11) co-segregated with glioma (DNAH11 p.Ser1470ArgfsTer6 and p.Thr3900Lys) and single families implicating Telomere Replication Complex Component 1 (CTC1 p.Leu1058ProfsTer32) and filamin alpha (FLNA p.Ser1356Phe). We complemented linkage analysis by WES of 150 additional unrelated familial glioma cases and conducting gene burden tests leveraging WES data on 691 cases of glioma from TCGA. Our analysis does not provide support for a hitherto unidentified major cancer gene for glioma but highlights a series of novel candidate predisposition variants/genes, worthy of further investigation to shed light on glioma risk.
ARTICLE | doi:10.20944/preprints202002.0255.v1
Subject: Biology, Entomology Keywords: BMSB; Halyomorpha halys; inherited sterility; irradiation; SIT
Online: 18 February 2020 (03:15:20 CET)
The irradiation biology of the brown marmorated stink bug (BMSB, Halyomorpha halys Stål) treated at the nymphal stage was investigated to determine its application for sterile insect technique (SIT). Fifth instar males of BMSB were exposed to gamma-radiation 60Co at different doses of 12, 16, 20, 24 and 64 Gy. Irradiated males were mated with non-irradiated virgin females to assess the longevity of both sexes, female fecundity and fertility of their offspring until the egg stage of the F2 generation. The mortality of each of the developmental stages of the F1 and eggs of the F2 generation was observed to determine whether negative effects from exposure to radiation was inherited. The data indicated that irradiation significantly reduced the lifespan of male insects at doses above 20Gy. Irradiated males did not affect the longevity and fecundity of their female partners, nor either sex of their resulting progeny, but it did reduce the hatch rate of the eggs at all doses tested. The sterility rates of F1 eggs were 55.6%, 73.3%, 74.1% and 74.1% at doses of 12Gy, 16Gy, 20Gy and 24Gy respectively. Eggs were completely sterile (100%) at a dose of 64Gy with no egg hatch recorded. A low hatch rate of F2 eggs illustrated that negative effects from radiation was inherited by the subsequent generation. The results support the potential for the use of SIT for BMSB management by irradiating the fifth instar male nymphs at 16-64Gy.
ARTICLE | doi:10.20944/preprints202206.0199.v1
Subject: Life Sciences, Biophysics Keywords: KCNQ1; Kv7.1; IKs; patch-clamp; inherited channelopathy; LQTS
Online: 14 June 2022 (08:42:22 CEST)
We identified a single nucleotide variation (SNV) (c.1264A>G) in the KCNQ1 gene in a 5-year-old boy who presented with a prolonged QT interval. His elder brother and mother, but not sister and father, also had this mutation. This missense mutation leads to a p.Lys422Glu (K422E) substitution in the Kv7.1 protein, never mentioned before. We inserted this substitution in an expression plasmid containing Kv7.1 cDNA and studied the electrophysiological characteristics of the mutated channel expressed in CHO-K1 using the whole-cell configuration of the patch-clamp technique. Expression of the mutant Kv7.1 channel in both homo- and heterozygous conditions, in the presence of auxiliary subunit KCNE1, results in a significant decrease in tail current densities compared to the expression of wild-type (WT) Kv7.1 and KCNE1. This study also indicates that K422E point mutation causes a dominant negative effect. The mutation was not associated with a trafficking defect, the mutant channel protein was confirmed to localize at the cell membrane. This mutation disrupts the poly-Lys strip in the proximal part of the highly conserved cytoplasmic A-B linker of Kv7.1, which was not shown before to be crucial for channel functioning.
ARTICLE | doi:10.20944/preprints202106.0275.v1
Subject: Medicine & Pharmacology, Allergology Keywords: inherited retinal disease; VUS; functional analysis; minigene assay
Online: 9 June 2021 (23:01:36 CEST)
Inherited retinal diseases (IRD) comprise a heterogeneous set of clinical and genetic disorders that lead to blindness. Given the emerging opportunities in precision medicine and gene thera-py, it has become increasingly important to determine whether DNA variants with uncertain significance (VUS) are responsible for the patients’ IRD. This research was performed to assess the functional consequence of six VUS identified in patients with IRD. Clinical assessments in-cluded an ophthalmic examination, best corrected visual acuity, and kinetic perimetry. Imaging was acquired with the Optos ultra-widefield camera and spectral-domain optical coherence to-mography (SD-OCT). Genetic testing was performed by Molecular Vision Laboratories. VUS that were predicted to alter splicing were analyzed with a minigene assay which revealed that VUS in the genes OPA1, CNGB1, and CLUAP1 altered spicing mechanisms. Due to the emerging gene and cell therapies, these results expand the genotype-phenotype correlations for patients diag-nosed with an IRD.
Subject: Medicine & Pharmacology, Other Keywords: inherited platelet disorders; hereditary thrombocytopenias; blood smear; immunofluorescence; bleeding tendency
Online: 20 January 2020 (09:50:59 CET)
Inherited platelet disorders (IPDs) are rare diseases featured by low platelet count and/or defective platelet function. Patients have variable bleeding diathesis and sometimes additional features that can be congenital or acquired. Identification of an IPD is desirable to avoid misdiagnosis of immune thrombocytopenia and use of improper treatments. Diagnostic tools include platelet function studies and genetic testing. The latter can be challenging as the correlation of its outcomes with phenotype is not easy. The immune-morphological evaluation of blood smear (by light- and immunofluorescence microscopy) represents a reliable method to phenotype subjects with suspected IPD. It is relatively cheap, not excessively time-consuming, and applicable to shipped samples. In some forms, it can provide diagnosis by itself, as for MYH9-RD, or in addition to other first-line tests as aggregometry or flow cytometry. In regard to genetic testing, it can guide specific sequencing. Since only minimal amounts of blood are needed for preparation of blood smears, it can be used to further characterize thrombocytopenia in pediatric patients and even newborns. In principle it is based on visualizing alterations in the distribution of proteins, which result from specific genetic mutations, by using monoclonal antibodies. It can be applied to identify deficiencies in membrane proteins, disturbed distribution of cytoskeletal proteins, and alpha as well as delta granules. On the other hand mutations associated with impaired signal transduction are difficult to identify by immunofluorescence of blood smears. This review summarizes technical aspects and the main diagnostic patterns achievable by this method.
ARTICLE | doi:10.20944/preprints202208.0106.v1
Subject: Life Sciences, Genetics Keywords: DPAGT1; Congenital Disorders of Glycosylation; sensitized chemical mutagenesis screen; mouse genetics; inherited retinal disease; ER Stress
Online: 4 August 2022 (07:08:13 CEST)
Congenital Disorders of Glycosylation (CDG) are a heterogenous group of primarily autosomal recessive mendelian diseases caused by disruptions in the synthesis of lipid linked oligosaccha-rides and their transfer to proteins. CDGs affect multiple organ systems and vary in presentation, even within families. Here we describe a chemically induced mouse mutant, tvrm76, with early onset photoreceptor degeneration. The recessive mutation was mapped to Chromosome 9 and as-sociated with a missense mutation in the Dpagt1 gene encoding UDP-N-acetyl-D-glucosamine:dolichyl-phosphate N-acetyl-D-glucosaminephosphotransferase (EC 188.8.131.52). The mutation is predicted to cause a substitution of aspartic acid with glycine at residue 166 of DPAGT1. Increased expression of Ddit3, and elevated levels of HSPA5 (BiP) sug-gest the presence of early-onset endoplasmic reticulum (ER) stress. These changes were associated with induction of photoreceptor apoptosis in tvrm76 retinas. Mutations in human DPAGT1 cause Myasthenic Syndrome 13 and severe forms of Congenital Disorder of Glycosylation Type Ij. In contrast, Dpagt1tvrm76 homozygous mice present with congenital photoreceptor degeneration without overt muscle or muscular junction involvement. Our results suggest the possibility of DPAGT1 mutations in human patients that present primarily with retinitis pigmentosa with little or no muscle disease. Variants in DPAGT1 should be considered when evaluating cases of non-syndromic retinal degeneration.
REVIEW | doi:10.20944/preprints202107.0377.v1
Subject: Earth Sciences, Atmospheric Science Keywords: Global salt cycle; Wilson cycle; Giant salt accumulations; Subduction; Rifting; Mantle; upwelling; Hydrated mantle; Hydrothermal salt expulsion; Hydrothermal circulation; Basin subsidence; Supercritical fluids; Phase separation; Saline brine; Salt diapir; Bedded salts; Inherited composition; Inherited structures; Lower crustal body; Electrical conductivity; Magnetotelluric method; Seismic velocity; Brittle-ductile behaviour; Continental crust formation; Oceanic crust formation; Hydration of oceanic crust; Serpentinization; Volcanism; Mineral solubility.
Online: 16 July 2021 (14:34:42 CEST)
The main objective of this communication is to describe the ‘Global Salt Cycle’. Giant salt accumulations are commonly found along continental margins of former rifts. The first stage in the accumulation process is saturation of newly formed oceanic crust with seawater. Final mobilisation and accumulation of the salts occurs during rifting, localised in the vicinity of relict subduction zones. Oceanic crust is created along the spreading ridges in the deep oceans of the Earth. It exchanges mass and energy with seawater in hydrothermal circulation cells that penetrate deep into the new and fractured crust. Water-rock interactions include the formation of hydrated and hydroxylated minerals, e.g., serpentinites and clay minerals. By incorporating hydroxyl groups and water in their crystal lattices, the salinity of remaining brines increases. Subduction of oceanic crust and serpentinised lithosphere transports water, hydrated minerals, and marine salts deep into the crust and mantle. Upon pressurisation and heating of the subducting slab, different parts of this water are expelled at different depths/temperatures. The resulting fluids will contain salts brought in with the slab, as well as new salts formed by water-rock interaction. The combination of elevated pressures and temperatures, water, salinity, and CO2, create permeability in the normally impermeable, peridotitic mantle, by altering the fluid-rock dihedral angles of mineral grains. This P/T-determined intergranular permeability allows ascent of saline fluids, under lithostatic pressure, within the mantle wedge, or the slab itself. The fluids produce a mechanically weakened and buoyant zone within the mantle wedge due to high pore pressure between mineral grains and reduced mantle density. During the lifetime of a subduction zone, a substantial accumulation of saline fluids within the mantle wedge and crust, is evident. Deep, fluid reservoirs accumulate between the subduction trench and the volcanic front. They may exist for hundreds of millions of years, even after the extinction of the subduction zone. Saline fluids may escape to the surface along deep faults, due to overfilling of available pores/fractures. Fluids within the mantle wedge may form rock melts or exist as supercritical, mineral rich fluids. The combination of reduced pressure due to rifting, and a saline and buoyant mantle, creates a mantle circulation that brings the accumulated, saline fluids, to crustal levels. Salts will therefore accumulate during initial stages of rifting as a result of massive fluid expulsion, phase change and boiling of mantle fluids. No extra energy is required to produce phase change and boiling. The result is formation of solid salts or dense brines/slurries invading fractured crustal rocks, or escaping to the surface/seabed. This process may take place both before and after the sea has invaded a continental rift.