Direct DNA sequence determination of PCR amplified exons of the tyrosinase gene of three British patients suffering from tyrosinase negative oculocutaneous albinism has revealed three new missense point mutations: (1) an adenine to guanine transition at codon 1 changes the initiating methionine codon into a valine codon thereby abolishing translation; (2) a thymine to cytosine transition at codon 370 changes a methionine to a threonine residue; (3) a cytosine to thymine transition at codon 367 changes a histidine to a tyrosine residue. A codon 402 change previously considered a polymorphism is assigned a pathological role.