The term albinism refers to a heterogeneous group of congenital disorders in melanin pigment biogenesis. Pigmentation process maybe affected in one or many ways due to mutations. Abnormal pigmentation maybe at the level of embryogenesis in regions where melanocytes fail to populate. The melanin biosynthetic pathway may also be affected due to mutations. Sometimes one or many of the genes responsible for biogenesis of organelles may be mutated.
Albinism may manifest itself as oculocutaneous (OCA) or just ocular (OA). There occur at least ten different types of OCA and four types of OA. OCA refers to a group of autosomal recessive disorders in which melanin is reduced or even absent leading to pale skin with increased risk of skin cancer. OCA1 is caused due to mutations in tyrosinase gene affecting its catalytic or synthetic activity. OCA2 is a condition where TYR gene is not mutated but the P polypeptide is. Mutational defects in TRP-1 protein leads to OCA3.
Ocular albinism results from defects in the melanin system, which may arise from either defects in the OA1 receptor, or mutations of either the Tyr gene or P transporter.
Read more about this topic: Ocular Albinism Type 1