CDKN2A and familial melanoma: In the Netherlands, the most common cause of familial melanoma is a CDKN2A founder mutation which is a deletion of 19 bp in exon 2 (c.225_243del, p.(A76Cfs*64); RefSeq NM_000077.4), also known as the p16-Leiden mutation resulting in inactivation of tumor-suppressive properties of p16(INK4a) [2].