CDKN2A and familial atypical multiple mole melanoma syndrome: In the Netherlands, a founder mutation in the CDKN2A gene, a 19-base pair deletion called p16-Leiden (c.225_243del19; RefSeq NM_000077.4), is the most common cause of Familial Atypical Multiple Mole Melanoma (FAMMM) syndrome [2].