A protein-truncating mutation in the gene, 1100delC, was associated with a two-fold increase in breast cancer risk in the CHEK2 Breast Cancer Case–Control Consortium pooling project, which comprised 10 860 breast cancer cases and 9065 controls from 10 studies in five countries (The CHEK2 Breast Cancer Case–Control Consortium, 2004). The gene discussed is CHEK2; the disease is breast cancer.