Telomeres are crucial structures that preserve genome stability. Their progressive erosion over rounds of DNA duplication determines senescence of cells and organisms. In a classic view, telomere biology impinges on intracellular signaling pathways regulating DNA damage repair and cell cycle arrest, but new roles of telomeric proteins and transcripts emerge from recent literature. Telomere biology diseases are human disorders associated to telomere attrition. This review wants to overview the recent findings in the field of telomere’s metabolism and to deepen molecular mechanisms of inherited and acquired telomeropathies, explaining new critical connections between telomeric factors and disease pathogenesis