The first disorder identified as a primary telomeropathy was dyskeratosis congenita, which is caused by mutations in the DKC1 gene encoding the dyskerin protein, or one of the core telomerase genes encoding a protein involved in telomere maintenance [116], resulting in telomere shortening, and thereby, premature aging [117,118]. This evidence concerns the gene DKC1 and dyskeratosis congenita.