Four individuals (4/52, 7.7%) were heterozygous for a constitutional pathogenic variant of a known breast cancer-associated gene, i.e. c.5179 A > T (p.Lys1727Ter) and c.181 T > G (p.Cys61Gly) in the BRCA1 gene, c.509_510del (p.Arg170fs) and c.354del (p.Thr119fs) in the PALB2 and RAD50 genes, respectively (Supplementary Table 3). Here, BRCA1 is linked to breast cancer.