MC1R and melanoma: In addition, co-inheritance of the cyclin-dependent kinase inhibitor (CDKN2A) gene and variants of the melanocortin-1 receptor (MC1R) gene that have previously been associated with red hair, fair skin and sensitivity to ultraviolet light (Arg151Cys, Arg160Trp, and Asp294His) have been found to significantly increase melanoma penetrance and decreased the age of onset by 20 years compared to individuals carrying the CDKN2A mutation alone [36].