What is albinism?
Albinism is a genetic condition resulting in a lack of pigmentation in the eyes, skin and hair. It is an inherited condition arising from the combination of recessive genes passed from both parents of an individual. A variety of problems with photosensitivity in eyesight and skin usually result from the condition. This entry is intended to cover mainly human albinism,
although many of the features mentioned would probably also apply to albinism in animals.
The word "albinism" refers to a group of inherited conditions. People with albinism have little or no pigment in the eyes, skin, and hair (or in some cases in the eyes alone). They have inherited from their parents an altered copy of a genes that does not work correctly. The altered gene does not allow the body to make the usual amounts of a pigment called melanin.
Albinism is a very serious disease that could end up in death. Albinism is a recessive inherited defect in melanin, which is metabolism in which pigment is absent from skin, hair, and eyes. Albinism in hair, skin, and eyes is called oculocutaneous albinism. Humans that have oculocotaneous albinism are not able to produce melanin. These people have white, yellow, or yellow brown hair, very light ( usually blue ) eyes, and very pale skin. Their eyes may appear pink because they have very little pigment.
There are two types of OCA, type I and type II. The classification of oculocutaneous albinism depends upon the nature of the underlying genetic defect. When a mutated tyrosinase gene produces inactive, less active, or temperature-sensitive tyrosinase, its phenotype is described as tyrosinase-negative (type I-A), yellow-mutant (type I-B), or temperature-sensitive (type I-TS) OCA, respectively. Mutation of the P gene encoding the tyrosine-transporting membrane protein probably occurs in tyrosinase-positive OCA (type II).
Oculocutaneous albinism type I is an autosomal recessive disorder characterized by absence of pigment in hair, skin, and eyes, and does not vary with race or age. Severe nystagmus, photophobia, and reduced visual acuity are common features. In contrast, the lack of pigmentation does not obstruct the normal growth and development of the skin or hair.