Phase 1 sequenced 14 previously reported HBOC genes (CHEK2, PALB2, ATM, TP53, RAD51C, RAD51D, CDH1, BARD1, PTEN, MRE11A, BRIP1, STK11, RAD50 and NBN) and 1303 candidate genes (Supplementary Data) in up to 1990 non-BRCA1/2 familial BC index cases and 1902 female controls. Here, CHEK2 is linked to breast cancer.