• Question: What causes albinism (albinos)?

    Asked by bridget to Amy, Drew on 24 Jun 2011.
    • Photo: Amy MacQueen

      Amy MacQueen answered on 24 Jun 2011:

      Hi bridget!!

      As you know Albinism is a disease in which a person has partial or complete loss of pigmentation (colouring) of the skin, eyes and hair.

      But what is it caused by? Well it involves the production of a pigment called melanin (which is what causes you to go brown when you get a tan). There is a cell called the melanocyte that is responsible for giving skin, hair, and eyes pigmentation. In albinism, the melanocytes are present, but genetic mutations interfere with their pigment production or their ability to distribute it to keratinocytes (this is the major cell type which makes up the outer layer of the skin).

      There are currently five known genetic types of albinism, the most common being oculocutaneous type 1 (OCA1) and type 2 (OCA2). Oculocutaneous means affecting the eyes and skin (“oculo” meaning eye and “cutaneous” meaning skin).

      Patients with OCA1 have mutations in a gene called TYR that is responsible for creating the enzyme tyrosinase, used by cells to convert the amino acid tyrosine into pigment molecules that colour the skin, hair, and eyes. OCA2, the most common form of albinism in Africa, results from a mutation in the OCA2 gene, which encodes the P protein. We don’t know what this P protein does yet!

      Hope that answers your question! 🙂

      p.s. thanks for your questions Bridget you really are a thinker I have been really enjoying answering them!