Medium-penetrance (3 ≤ RR ≤ 10) genes such as CHEK2, ATM, PALB2 (suggested by some as being high-penetrance4,5), BRIP1 (disputed as a breast cancer susceptibility gene by some6) have also been identified and account for about 8% of inherited breast cancers cases2. The gene discussed is ATM; the disease is breast carcinoma.