The remaining other breast cancer cases (13/21) were carriers of a heterozygous PV in genes associated with autosomal recessive inheritance syndromes (i.e., MUTYH, FANCA, NTHL1, XPC, REQL4, BLM, NBN, BUB1B, and ERCC4) and did not receive a diagnosis of a hereditary cancer syndrome. This evidence concerns the gene NBN and breast cancer.