OCA2 and oculocutaneous albinism: To date, biallelic mutations in 6 distinct genes (7 loci, OCA1–OCA7) have been described in nonsyndromic OCA (4); of these, mutations in the tyrosinase (TYR, OCA1) gene and the OCA2 gene (formerly, the P gene) are the most prevalent forms of OCA in North America (3, 5).