Why Are People Born Albino?

Types

• Scientists divide albinism into several categories. Oculocutaneous albinism, or OCA, is the most common and affects the skin, hair and eyes. Ocular albinism, or OA, mainly affects the eyes. A defective chemical called tyrosinase, which helps create pigment, causes OCA1. In OCA1A, the tyrosinase is completely inactive, and no pigment is created. In OCA1B, some pigment is produced. A defective protein that helps the tyrosinase work properly causes OCA2. People with OCA2 have a small amount of melanin and light blonde to brown hair. A genetic defect in a protein related to tyrosinase called TYRP1 causes OCA3. People with OCA3 can have a lot of pigment. A defect in a protein called SLC45A2, which helps tyrosinase work properly, causes OCA4. People with OCA4 have a small amount of pigment.

Genetics

• The genes that cause OCA are found on the chromosomes, which determine a person's general physical characteristics. However, albinism is a recessive trait, so a child will only be an albino if he inherits the defective gene from both parents. A defective gene found on the X chromosome -- one of two that determine a person's sex -- causes OA. Females inherit two X chromosomes while males inherit an X chromosome from their mother and a Y chromosome from their father. OA primarily occurs in males who have inherited the defective gene from their mothers.

Problems

• All albinos suffer from eye problems. The abnormal development of nerve connections between the eyes and brain and the irregular development of the retina cause the eye problems. Eyeglasses cannot correct these vision problems. Although albinos are considered legally blind, most albinos have strong enough vision for reading and other tasks, and some can even drive. Albinism is typically diagnosed by testing for these vision problems. Albinos with many forms of albinism must also protect their skin from sun damage by using hats, sunscreen and protective clothing.

History

• Until the late 17th century, most Europeans considered albinos pale-skinned blondes. However, in the 18th century, the French scientists Comte Buffon and Abbe Demanet argued that since albinos were common among dark-skinned people in Africa and the tropics, the original skin color was white before people migrated to those areas and developed dark skin. In the 20th century, the scientific community's acceptance of Gregor Mendel's theory of how parents pass genetic information to their offspring generally ended such racist theories. However, the Nazis and their supporters continued denigrating albinos as subhuman.