Albinism, caused by a deficiency of melanin pigment in the skin, hair, and eye 
(oculocutaneous albinism [OCA]), or primarily in the eye (ocular albinism [OA]), 
results from mutations in genes involved in the biosynthesis of melanin pigment. 
The lack of melanin pigment in the developing eye leads to fovea hypoplasia and 
abnormal routing of the optic nerves. These changes are responsible for the 
nystagmus, strabismus, and reduced visual acuity common to all types of 
albinism. Mutations in six genes have been reported to be responsible for 
different types of oculocutaneous and ocular albinism, including the tyrosinase 
gene (TYR) and OCA1 (MIM# 203100), the OCA2 gene and OCA2 (MIM# 203200), the 
tyrosinase-related protein-1 gene (TYRP1) and OCA3 (MIM# 203290), the HPS gene 
and Hermansky-Pudlak syndrome (MIM# 203300), the CHS gene (CHS1), and 
Chediak-Higashi syndrome (MIM# 214500), and the X-linked ocular albinism gene 
and OA1 (MIM#300500). The function of only two of the gene products is known 
tyrosinase and tyrosinase-related protein-1 both of which are enzymes in the 
melanin biosynthetic pathway. Continued mutational analysis coupled with 
function/structure studies should aid our understanding of the function of the 
remaining genes and their role in albinism. Mutation and polymorphism data on 
these genes are available from the International Albinism Center Albinism 
Database web site (http://www.cbc.umn.edu/tad).