All three DC cases (no. 20–22) carried MLH1 and POLD1 mutations with TMB-H and MSI-H, and exhibited variable mutations in PTEN, ARID1A, PIK3CA, PIK3R1, and CTNNB1. The TERT coding region was mutated in two DC cases, although the promoter was not. Here, PTEN is linked to dyskeratosis congenita.