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Albinism
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Albinism is a group of inherited disorders that share a total or partial lack of melanin, the pigment responsible for color. One of its types is oculocutaneous albinism, the kind that affects the eyes and the skin. It affects the tissues that come from the ectoderm, the embryonic layer that forms the body's outer covering: mainly the skin, the hair and the eyes.
The surprise is where the failure happens. The melanocytes, the cells of the epidermis that make the pigment, are there and in their usual numbers. The pigment factories are still in place; the production line stops.
Within that line there is a first step that sets the pace for everything else: converting L-tyrosine, an amino acid, into the material that eumelanin, the brown and black pigment, comes from. Tyrosinase, an enzyme, is what carries out that conversion. When its gene is mutated, as in the type called OCA1A, that step does not happen and eumelanin is not produced.
In brief
Albinism is a group of inherited disorders with reduced or absent melanin in tissues derived from the ectoderm, mainly the skin, hair and eyes.
In oculocutaneous albinism, one of its types, the number of melanocytes in the epidermis is unchanged; what fails is melanin synthesis.
The pigment factories are still in place; the production line stops.
The rate-limiting step of eumelanin synthesis is the oxidation of L-tyrosine by tyrosinase; a mutation in its gene, as in OCA1A, prevents eumelanin from being made.
Sources (1)
- National Center for Biotechnology Information, StatPearls PublishingAlbinism, StatPearlsPublished
This page explains the topic in general terms; it does not tell anyone what treatment to follow.
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