Albinism is a genetic condition that affects the production of melanin, the pigment that gives skin, hair, and eyes their color. It is caused by a mutation in one of several genes responsible for the production of melanin. Most cases of albinism are inherited in an autosomal recessive pattern, meaning that both parents must carry the mutated gene for a child to be born with albinism.
There are two primary types of albinism: oculocutaneous albinism (OCA) and ocular albinism (OA). OCA is the most common type, and it affects the skin, hair, and eyes. Ocular albinism is much less common and only affects the eyes.
The most common gene mutation associated with OCA is the P gene, which is located on the long arm of chromosome 15. Mutations in the P gene can cause several different types of OCA, including OCA1, OCA2, and OCA3. Mutations in the TYR gene, located on the short arm of chromosome 11, can also cause OCA.
OA is caused by mutations in the GPR143 gene, located on the X chromosome. Mutations in this gene can cause a variety of symptoms, including reduced visual acuity, nystagmus, and photophobia.
In addition to these gene mutations, albinism can also be caused by spontaneous mutations in the genes mentioned above. These mutations are not inherited, but are caused by environmental factors such as exposure to ultraviolet light.
In summary, albinism is a genetic condition caused by mutations in one or more of several genes responsible for the production of melanin. Mutations in the P gene, located on chromosome 15, and the TYR gene, located on chromosome 11, can cause oculocutaneous albinism, while mutations in the GPR143 gene, located on the X chromosome, can cause ocular albinism. Spontaneous mutations caused by environmental factors can also play a role in the development of albinism.