POT1 and familial melanoma: While PVs have also been detected in several other genes, including CDK4 [3, 4, 5, 6], BAP1 [3, 8, 9], ATM [10], MITF [3, 9, 13] and multiple telomere stability genes TERT, POT1, ACD, and TERF21P [3, 9, 11, 12], about half of the cases of familial melanoma remain unexplained.