Definition   

Albinism refers to a group of related conditions. These conditions are the result of altered genes that cause a defect of melanin production. This defect results in the partial or full absence of pigment from the skin, hair, and eyes.

Causes and risks   

An amino acid called tyrosine is normally converted by the body to the pigment melanin. Albinism results when the body is unable to produce or distribute melanin because of one of several possible defects.  In particular, defects in the metabolism of tyrosine leading to failure to convert it into melanin, can cause albinism.

Albinism appears in different forms and may be inherited by one of several modes: autosomal recessive, autosomal dominant, or X-linked. Complete albinism involves a total absence of pigment from the hair, eyes, and skin (this is also called tyrosinase-negative oculocutaneous albinism). It is the most severe form of the condition. Affected people may appear to have hair, skin, and iris color that are white as well as vision defects. They also have photophobia (sunlight is painful to their eyes), they sunburn easily, and do not tan.

Albinism of just the eyes also occurs. This is called Ocular albinism. In this form of albinism skin color is usually normal and eye color may be in the normal range, however, examination of the retina will show that there in no pigment in the retina.

Prevention   

As this is a large group of inherited conditions genetic counseling is important. Genetic counseling should be considered for individuals with a family history of albinism or hypo pigmentation.

Symptoms   

Absence of pigment from the hair, skin, or iris of eyes

• patchy absence of pigment (skin color, patchy) including in the carrier-Mothers of affected boys with X-linked recessive albinism
• lighter than normal skin and hair, complete albinism

Most forms of complete albinism have some of the following possible symptoms:

• rapid eye movements (nystagmus)
• strabismus (eyes not tracking properly)
• photophobia (avoidance of light because of discomfort)
• decreased visual acuity
• functional blindness

Signs and tests   

The most accurate way to determine albinism and the specific type is genetic testing. This is helpful only in families with albinism and is not useful for the general population. A small blood sample is obtained from the affected individual and the parents and genetic analysis of the DNA code is performed to identify the affected genes.

The disorder may also be diagnosed based on the appearance of the skin, hair, and eyes. It is very helpful for an ophthalmologist to perform a complete examination of anyone with albinism. A electroretinogram test, to determine brain waves produced by light shined in the eye, can reveal 'abnormal wiring' of the visual system in ocular forms of albinism.

Treatment   

Treatment aims to ease symptoms and depends on the extent of the disorder.

The skin and eyes must be protected from the sun. Sunglasses (UV protected) may relieve photophobia. Sunburn risk can be reduced by avoiding the sun, the use of sunscreens and complete coverage with clothing when exposed to sun. Sunscreens should have a high SPF (sun protection factor).

Prognosis   

Albinism does not affect the expected lifespan. Activities may be limited by intolerance to the sun.

Complications   

·        Skin cancer

·        Decreased vision, blindness