In this study of 564 women with DCIS, 57 (10.1%) carried a founder non-BRCA mutation in one of the three genes including variants in CHEK2 (c.1100delC, c.444 + 1G > A, del5395 and c.470T > C), PALB2 (c.509_510delGA) and NBN (c.657_661delACAAA). This evidence concerns the gene NBN and ductal breast carcinoma in situ.