The four most common genetic subtypes of DC are those that involve either the core components of the telomerase complex [23], the RNA (TERC), the reverse transcriptase (TERT) and the accessory protein dyskerin (DKC1), or the shelterin component, the telomeric repeat binding factor 1-interacting nuclear factor 2 (TINF2). The gene discussed is DKC1; the disease is dyskeratosis congenita.