Biochemical classification

Albinism may be classified biochemically into two groups (1):

• tyrosinase negative - the loss of tyrosinase activity interferes in the conversion of tyrosine to melanin
  
  
• tyrosinase positive:
  • in some tyrosinase positive albinos there is a defect in a putative tyrosine transporter molecule called protein P
  • in the Chediak-Higashi and Hermansky-Pudlak syndromes there is a defect in the transfer of melanosomes to the keratinocytes

Reference:

• Lee, S.-T. et al., Mutations of the P gene in oculocutaneous albinism, ocular albinism and Prader-Willi syndrome plus albinism, New Engl. J. Med., 1994, 330(8), p.529-34