Past studies have shown that a 50‐60% reduction of hTR levels in peripheral blood cells or fibroblasts from DKC1‐mutated DC patients is sufficient to lead to telomere shortening and disease [33, 34]; the 80% reduction in hTR observed in the patient in this study therefore provides a molecular explanation for his short telomeres. This evidence concerns the gene TERC and dyskeratosis congenita.