BRCA1 and pachyonychia congenita: The frequency of mutations in the high- and moderate-risk PC predisposition genes was increased in patients with PC with a personal history of breast cancer (Table 3), with almost two-fold more mutations observed in ATM (6.80%), BRCA2 (6.50%), PALB2 (3.38%), BRCA1 (2.00%), and TP53 (0.91%).