There are 13 genes (RYR2, IQCM, CTNND2, SDK1, MSR1, LINGO2, MALRD1, VTI1A, UNC13C, CACNA1H, AC104151.1, ZNF100, CBFA2T2) that contain partial CNV deletions in both BD‐cancer and BD‐only patients, but the deleted parts are different, and they show good trend of enrichment in synapse organization among the BD‐cancer cases (FDR = 0.071). This evidence concerns the gene UNC13C and cancer.