Albinism is a genetic metabolic skin condition that is passed down from one generation to the next through inheritance. It usually affects the skin and hair, and less commonly the eyes. People with albinism are called albinos.
ALBINISM is the complete absence, or very low levels, in the body of melanin, the pigment that gives colour to our skin, hair and eyes.
Melanin is a dark pigment known as a "light protector". The main function of melanin in the skin is to prevent damage to the skin by blocking ultraviolet rays from the sun. Sunlight causes melanin in the skin to increase, resulting in a tan. Most people with albinism have no melanin in their bodies, and their skin does not tan when exposed to the sun. As a result, their skin is very sensitive to sunlight and, if not properly protected, burns can occur.
In albinos (both humans and animals), the skin is very thin and whitish (or slightly pink), and the hair (or fur) is white. The pupils of the eyes appear pink, and light reflected from the retina appears red. The eyes are sensitive to light and often astigmatic. Because of the eyes' sensitivity to light, nystagmus (involuntary eye movement) is present. Although rare, albinism can be accompanied by intellectual or physical disability. Because their skin contains little or no colour pigment, harmful rays from the sun penetrate the body, and excessive sun exposure can even be fatal.
Melanin is also active in other parts of the body, such as the eyes and brain. In the eye, melanin is found in the retina and in the area of the retina called the fovea. Because of the lack of melanin during the body's development, vision does not develop fully. Other areas of the retina develop normally whether melanin is present or not. In a normal eye, the iris also contains melanin, which makes the iris opaque to light. In albinism, there is little or no pigment in the iris, so the iris is very sensitive to light.
Risk factors for albinism
Albinism in the family – Genetic factor: The albinism gene is recessive. Currently used prenatal tests cannot detect albinism. The children of a person without albinism and a person with albinism will be carriers, but none of the children will have albinism. For a child to have albinism, both parents must be carriers. For two carrier parents, in each pregnancy the chance of having a child with albinism is 25%, the chance of the child being a carrier is 50%, and the chance of the child being completely unaffected is 25%. Having one parent with albinism greatly increases the likelihood of the child having albinism, and even its presence in the wider family history is a major risk factor.
Sex: Albinism has been found to be more common in girls.
Types of albinism:
There are 8 different types of albinism, depending on the gene affected. Only 6 types are listed in the table below. 2 types were discovered in 2013 and have not yet been classified.
Oculocutaneous albinism (OCA): This is the most common type of albinism. There is no colour at all in the eyes, skin and hair (and all body hair). Because their whole body is white, they are greatly affected by the sun, since without melanin the sun's harmful rays pass directly to the underlying cells. In sunny weather (and in summer, even on cloudy days), from a very young age they should go outside wearing dark-lensed sunglasses and a hat and using sunscreen.