What Causes Albinism?
Albinism is an inherited disease characterized by a substantially lower rate of melanin production. This article explores albinism causes and symptoms.
What Causes Albinism?
A defect in one of several genes that produce or distribute melanin causes albinism. The defect may result in the absence of melanin production, or a reduced amount of melanin production. The defective gene passes down from both parents to the child and leads to albinism.
One in 70 people carry the gene for albinism. The genes in question are responsible for various aspects of the production of melanin by melanocytes in the skin and eyes. Most commonly, the mutations interfere with the enzyme tyrosinase (tyrosine 3-monooxygenase). This enzyme synthesizes melanin from the amino acid tyrosine.Depending on the mutation, melanin production can either be slowed or completely stopped. Regardless of the amount of interference with melanin production, there are always problems with the visual system. This is because melanin plays a vital role in the development of the retina and the optic nerve pathways from the eye to the brain.
Types of Albinism
Albinism is split into a number of subgroups depending on the specific genes that are affected.
Oculocutaneous albinism (OCA): This is caused by a mutation in 1 of 4 genes. OCA is further split into seven types depending on the mutations. These subdivisions include:
- OCA type 1: Individuals tend to have milky skin, white hair, and blue eyes. With age, some individuals' skin and hair may darken.
- OCA type 2: Less severe than type 1, this occurs most often in sub-Saharan Africans, African-Americans, and Native Americans.
- OCA type 3: Vision problems are normally milder than in other types. This mostly affects black South Africans.
- OCA type 4: This is most common among East Asian populations. It appears similar to type 2.
X-linked ocular albinism: This is caused by a gene mutation of the X chromosome. X-linked ocular albinism mainly affects males. Vision problems are present, but eye, hair, and skin color is generally in the normal range.
Hermansky-Pudlak syndrome: This rare variant is most common in Puerto Rico. The symptoms are similar to oculocutaneous albinism but bowel, heart, kidney, and lung diseases or bleeding disorders, such as hemophilia and more likely, too.
Chediak-Higashi syndrome: This is a rare form of albinism, caused by a mutation in the CHS1/LYST genes. Symptoms are similar to oculocutaneous albinism but hair can appear silvery, and the skin can look slightly gray. There may be defects in the white blood cells, making infections more common.
As research continues, science will discover more specific mutations, helping us understand the underlying causes of albinism in more detail.
The process of diagnosing albinism involves:
- a physical exam
- discussion about skin and hair pigmentation changes
- an examination of the eyes by an expert (ophthalmologist)
- comparing the individual's coloration with that of family members
Other diseases can also cause changes in pigmentation, but they will not cause changes in vision. If pigment changes and vision changes are both present, albinism is very likely to be the cause. The most reliable way to diagnose albinism is with genetic testing. However, in families with a history of albinism, this is not always necessary.
Because the disease is genetic, there are no cures. Treatment focuses on minimizing the symptoms and watching for changes. Getting the right care for eye problems is essential.
- prescription glasses
- dark glasses to protect the eyes from the sun
- regular eye exams
You should watch for any skin changes and use sunblock for protection. Surgery on the optical muscles can sometimes minimize the "shaking" in nystagmus. Procedures to minimize strabismus can make it less noticeable, but surgery will not improve vision. The level of success in reducing symptoms varies between individuals. Albinism does not worsen with age. A child with albinism can flourish and achieve the same education and employment as a person without the condition.
The most common physical problems associated with albinism are the risk of sunburn and skin cancers. Additionally, some people face significant social issues. These may include bullying at school. The person may feel like an outsider because they look different. These social factors can lead to stress, low self-esteem, and isolation. Individuals with albinism in sub-Saharan Africa face the most significant difficulties.
A study carried out in Nigeria reported that they "Experienced alienation, avoided social interactions and were less emotionally stable. Furthermore, affected individuals were less likely to complete schooling, find employment and find partners." In some sub-Saharan countries, such as Tanzania and Burundi, the body parts of individuals with albinism are sought after by witch doctors.
There are numerous cases where children with albinism were murdered for profit. National Geographic estimated that in 2013, the body parts of a person with albinism could make up to $75,000. In some African countries, Tanzania and Zimbabwe particularly, some people believe that having sex with a woman with albinism cures AIDS. This false belief has led to murder, rape, and additional AIDS infections. In 2015, the United Nations called for "urgency" in taking measure to prevent attacks on people with albinism.