Furthermore, Slavic breast cancer patients have a high mutation frequency of BRCA1: c.4035del; p.(Glu1346fs); CHEK2: c.1100del; p.(Thr367fs) and deletion of exon 9–10; BLM: c.1642C>T; p.(Gln548Ter); ATM: c.5932G>T; p.(Glu1978Ter); and NBN: c.657_661del; p.(Lys219fs) mutations [10,11,12,13,14], resulting in a higher frequency of DH identified in these populations. Here, BRCA1 is linked to breast cancer.