Inherited genetic defect(s) commonly associated with melanocytic transformation are the cell cycle regulating genes, CDKN2A, and CDK4, a gene associated with skin pigmentation, MC1R, and the genetic disorder xeroderma pigmentosum (XP), occurring as a result of mutations within the nucleotide excision repair (NER) machinery [6,7,8,9,10,11,12,13,14]. The gene discussed is CDK4; the disease is xeroderma pigmentosum.