Statistics for Oculocutaneous and Ocular Albinism


Albinistic man portrait, Image from Wikimedia CommonsAlbinism or medically known as congenital hypopigmentary disorder is a genetic disease that affects people from all races. The condition is also observed in some species of mammals, fishes, birds, reptiles, and amphibians. An individual with albinism is commonly called “albino.”

Some countries have larger albino population than others. An example is the east African country Tanzania which has an estimated 200,000 people with albinism. From 2006-2008, more than 57 Tanzanian people with albinism were attacked, mutilated, or killed for their highly priced body parts used by witchdoctors to make “magical potions.” This is an example on how people with albinism are being persecuted in the name of witchcraft.

Disregarding vision problems and lack of hair and skin pigmentations, albinistic people have normal growth and mental development. However, some of them have poor social skills because they are often viewed “differently” by normal people in the society. It is not uncommon for an albinistic person to be teased or ridiculed by other people especially in his/her adolescent years. These situations affect their ability to mingle with other people confidently. Fortunately, there are albinistic people who gained fame by showcasing their talents to the public. Read the article on famous people with albinism.

Statistically, about 1 in 17,000 people suffer from some form of albinism. There are two forms of albinism: the Oculocutaneous albinism (OCA) and Ocular albinism. There are also certain diseases with albinism as a symptom.

Oculocutaneous Albinism Statistics


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Oculocutaneous albinism is the most common form of albinism with symptoms affecting the skin, eyes, and hair. Individuals with the condition generally lack pigmentation in the skin, hair, and the iris. There are three types of oculocutaneous mutation based on the specific gene involved: OCA types 1, 2, and 3.

OCA type 1 occurs in 1 person per 40,000 people. This type of oculocutaneous mutation is caused by a defect in a gene located in human chromosome 11 and is inherited as an autosomal recessive trait, which means that an individual must inherit 2 defective genes from his/her parents for the disorder to occur.

OCA type 2 is caused by a defect in the gene found in chromosome 15 and is also inherited as an autosomal recessive trait. Statistics for OCA type 2 albinism shows that there is 1 affected individual per 15,000 people.

Defect in a gene on chromosome 9 causes OCA type 3 which is genetically confirmed in African and African-American individuals. The prevalence of OCA type 3 in the population is not yet known.

Ocular Albinism Statistics

Ocular albinism accounts for 10 to 15 % of albinism cases. An individual with this type of albinism lacks pigmentation in the irises and has vision problems. Ocular albinism is an X-linked genetic disorder, meaning the defective gene (GPR143 gene) is located in the X chromosome. A male has one X chromosome and a female has two X chromosomes. A male automatically develop ocular albinism once he inherits an X chromosome with the defective gene. According to NIH, there is about 1 for every 60,000 men who suffer from ocular albinism. On the other hand, a female will only develop ocular albinism if she inherits 2 X chromosomes with the defective genes. Females have lower chance of inheriting the gene for ocular albinism than males.

Disorders with Albinism as a Symptom

Albinism is a symptom of Waardenberg syndrome, Chediak-Higashi syndrome, tuberous sclerosis, and Hermansky-Pudlak syndrome.[ad#afterpost]

References

Albinism Incidence – About.com

NIH – Ocular Albinism