To investigate whether cancer-associated mutations in the FeS domain affect FeS cluster binding, we included FANCJ C283R, associated with early-onset prostate cancer and classified as potentially pathogenic [23]; FANCJ L340F, associated with familial breast cancer and predicted to be likely pathogenic [22]; and the previously studied FANCJ M299I, found in a patient with early-onset breast cancer and proposed to be hyper-active [1,21,24]. The gene discussed is BRIP1; the disease is breast carcinoma.