P gene as an inherited biomarker of human eye color.
Human pigmentation, including eye color, has been associated with skin cancer risk. The P gene is the human homologue to the mouse pink-eye dilution locus and is responsible for oculocutaneous albinism type 2 and other phenotypes that confer eye hypopigmentation. The P gene is located on chromosome 15q11.2-q12, which is also the location of a putative eye pigmentation gene (EYCL3) inferred to exist by linkage analysis. Therefore, the P gene is a strong candidate for determination of human eye color. Using a sample of 629 normally pigmented individuals, we found that individuals were less likely to have blue or gray eyes if they had P gene variants Arg305Trp (P = 0.002), Arg419Gln (P = 0.001), or the combination of both variants (P = 0.003). These results suggest that P gene, in part, determines normal phenotypic variation in human eye color and may therefore represent an inherited biomarker of cutaneous cancer risk.