Definition of Albinism:

Albinism is a defect of melanin production that results in little or no color (pigment) in the skin, hair, and eyes.

Causes, incidence, and risk factors:

Albinism occurs when one of several genetic defects makes the body unable to produce or distribute melanin, a natural substance that gives color to your hair, skin, and iris of the eye.

The defects may be passed down through families.

There are two main types of albinism:

• Type 1 albinism is caused by defects that affect production of the pigment, melanin.
• Type 2 albinism is due to a defect in the "P" gene. People with this type have slight coloring at birth.

The most severe form of albinism is called oculocutaneous albinism. People with this type of albinism have white or pink hair, skin, and iris color, as well as vision problems.

Another type of albism, called ocular albinism type 1 (OA1), affects only the eyes. The person's skin and eye colors are usually in the normal range. However, an eye exam will show that there is no coloring in the back of the eye (retina).

Hermansky-Pudlak syndrome (HPS) is a form of albinism caused by a single gene. It can occur with a bleeding disorder, as well as with lung and bowel diseases.

Other complex diseases may lead to loss of coloring in only a certain area (localized albinism). These conditions include:

• Chediak-Higashi syndrome (lack of coloring all over the skin, but not complete)
• Tuberous sclerosis (small areas without skin coloring )
• Waardenburg syndrome (often a lock of hair that grows on the forehead, or no coloring in one or both irises)