Germline mutations in DKC1 result in XLR inheritance, mutations in TERC, TERT, RTEL1, or TINF2 result in AD inheritance, and mutations in TERT, RTEL1, CTC1, NOP10, NHP2, or WRAP53 result in AR inheritance [4]–[7], [8]; mutations in these genes account for approximately one-half of classic DC cases. This evidence concerns the gene AR and dyskeratosis congenita.