High-penetrance genetic variants in genes such as cyclin-dependent kinase inhibitor 2A (CDKN2A) (6), cyclin-dependent kinase 4 (CDK4) (7), telomerase reverse transcriptase (TERT) (8), protection of telomeres 1 (POT1) (9,10) and other telomere-associated genes are found in approximately half of melanoma-prone families (11), and are known to mediate risk for developing the disease. Here, CDK4 is linked to melanoma.