Mutations in the human P gene lead to oculocutaneous albinism type 2 (OCA2, MIM 
#203200), the most common type of albinism in humans. The P gene encodes a 110 
kDa protein that is associated with melonosomal membranes and contains 12 
potential membrane spanning domains. The specific function of the P protein is 
currently unknown. We report 7 new mutations in the P gene associated with OCA2. 
This includes 6 missense mutations (S86R, C112F, A368V, T592I, A724P and A787V) 
and one frameshift mutation (1047del7). We also report 8 polymorphisms including 
one amino acid substitution, D/A257. We and others have found many polymorphisms 
of the P gene in the coding region, several of which result in amino acid 
substitutions, making molecular diagnosis problematic. In contrast to this is 
the tyrosinase gene associated with OCA1, with a limited number of polymorphic 
variations in the coding region. There is also no apparent clustering of P gene 
missense mutations in contrast to the clustering observed by the tyrosinase gene 
missense mutations that define functional domains of the protein. Further 
mutational analysis is needed to help define the critical functional domains of 
the P protein and to allow a definitive diagnosis of OCA2.