This germline mutation was accompanied by normal allele somatic inactivation through various mechanisms (see below), consistent with a tumor suppressor role for ATM. F12 harbored a heterozygous germline FANCM nonsense mutation, p.Q1701*, predicted to truncate FANCM C-terminus, and shown to confer increased risk for breast cancer development [31]. Here, FANCM is linked to breast carcinoma.