Exons 11–13 encode multiple protein-binding sites6–9, including a coiled-coil domain that interacts with the product of the PALB2 breast cancer susceptibility gene10–12, allowing assembly of a BRCA1/PALB2/BRCA2 protein complex that can recruit RAD51 to the sites of DNA double strand breaks (DSBs) and thereby promote DSB repair by homologous recombination (HR)13,14. The gene discussed is BRCA1; the disease is breast cancer.