Mutations in the human tyrosinase gene produce tyrosinase-related oculocutaneous 
albinism (OCA1, MIM #203100). Tyrosinase is a copper containing enzyme and is 
responsible for catalyzing the rate limiting step in melanin biosynthesis, the 
hydroxylation of tyrosine to dopaquinone. We report 13 new mutations in the 
tyrosinase gene associated with OCA1A (without pigment) and OCA1B (with pigment) 
including 9 missense mutations (H19Q, R521, R77C, G97R, C289R, L312V, P313R, 
F340L and H404P), two nonsense mutations (W80X and R116X) and two frameshift 
mutations (53delG and 223 delG). Our previous work has defined clusters of 
missense mutations that appear to represent functional domains of the enzyme, 
and three of the missense mutations fall into these clusters including two 
(F340L and H404P) that flank the copper B bindng site and the missense mutation 
R52I that is located in the amino terminal end cluster of the protein. The G97R 
missense mutation is the first identified within the epidermal growth factor 
(EGF)-like sequence and the H19Q missense mutation alters the cleavage site of 
the signal peptide sequence. Mutational analysis can provide a definitive 
diagnosis of the type of OCA as well as help structure/function analysis.