Experts recommend germline testing in patients with a family history of hereditary PC criteria or other cancer syndromes (genes to be considered—BRCA2, BRCA1, ATM, CHEK2, PALB2, HOXB13, MLH1, MSH2, MSH6, PMS2, NBN, BRIP1, and TP53) and annual screening for BRCA2 carriers or other germline mutations starting at age 40 yrs and at the age corresponding to 10 yrs prior to the age of youngest family diagnosis of PC. The gene discussed is CHEK2; the disease is pachyonychia congenita.