Albinism is a genetic disorder that affects pigmentation of the skin, hair, and eyes. People with albinism are more sensitive to light and are at an increased risk for developing skin cancer. In addition, some suffer from vision impairments, nystagmus (involuntary eye movements), myopia, and more.
This disorder is caused by a gene mutation that can occur in several genes, all linked to production of a pigment called melanin which is produced by cells called melanocytes. More than ten types of albinism are known today.
What gene mutations cause albinism?
The common types of albinism are OCA1 and OCA2. The more prevalent type, called OCA1, is caused by a mutation to the gene encoded to the production of tyrosinase. This gene is called TYR, it is located on chromosome 11. Mutations in this gene cause disruptions in melanin production.
The second type of albinism is caused by a mutation to the gene OCA2, located on chromosome 13 and encoded to the production of a protein called the P protein (the exact function of this protein is still unknown).
OCA1 is divided into two subtypes:
- OCA-1A: this is the more severe form of the common type of albinism. People with this form have white hair, transluscent irises, skin that does not tan, nystagmus and severe vision impairments with vision acuity of 20/100 and even 20/400.
- OCA-1B: a milder form of albinism. Babies with this form are born with white hair that can darken with age and become yellow. The skin has minimal tanning ability. Vision impairments are milder, including nystagmus.
Most gene mutations that cause albinism are inherited in an autosomal recessive pattern.
Genetic testing
Prenatal testing for albinism is offered to parents with a child who has this condition. The relevant mutations can be detected through chorionic villus sampling or amniocentesis. These procedures require taking a fetal skin biopsy.
Treatment
There is no cure for albinism. However, treatment can help manage this condition and relieve symptoms. A major part of treatment is protecting the eyes and skin from sunlight, this can be achieved through using sunscreen, wearing protective clothing, and using UV protected sunglasses. Appropriate eyeglasses can help correct vision impairments. In some cases, eye surgery may be required.
Although albinism may limit a person’s outdoor activities (due to sensitivity to the sun), this condition does not affect lifespan.
