Mutations in ATM, BRCA2, CDKN2A, MSH2, MSH6, PALB2, and TP53 were significantly associated with high risk of PC (OR, > 5), whereas deleterious mutations in CHEK2 and BRCA1 were associated with moderate risk (OR, > 2; Table 2). The gene discussed is CHEK2; the disease is pachyonychia congenita.