Genotypes for Pigmentation and Skin Cancer

The genetic bases for skin pigmentation — and skin cancer — are slowly being uncovered through a series of genome-wide association studies (GWAS). In 2007, scientists in Iceland examined the association of DNA variants with eye, hair, and skin traits (JW Dermatol Nov 30 2007).

In subsequent analysis, the same research group has expanded its genome-wide scan, finding three loci that appear to strongly correlate with these pigmentary phenotypes. One large region containing agouti protein was associated with red hair, freckling, and sun sensitivity, including sunburn — a phenotypic pattern reminiscent of MC1R variants. In melanocytes, the agouti protein antagonizes the activation of MC1R by α-MSH, resulting in the production of pheomelanin. The…