Albinism refers to a range of disorders that result from a reduction or absence of the pigment melanin. These vary in severity and often causing white skin, light hair, and vision problems.
The condition can affect anyone, but its prevalence varies by region.
In sub-Saharan Africa, albinism affects one in every 5,000 to 15,000 people. Among some groups, the rate is as high as 1 in 1,000 to 5,000. In Europe and the United States, it is closer to 1 in 17,000 to 20,000.
Albinism affects the sexes evenly, and all ethnic groups are susceptible.
Fast facts on albinism
Here are some key points about albinism. More detail and supporting information is in the main article.
There is no cure for albinism, but some symptoms can be treated.
Albinism is a genetic condition.
Primarily, albinism affects the hair, eyes, skin, and vision.
The most common cause of albinism is an interruption in the functioning of the enzyme tyrosinase.
An estimated 1 in 70 people carry the genes associated with albinism.
What is albinism?
Albinism is an inherited disease characterized by a substantially lower rate of melanin production.
Melanin is the pigment responsible for the color of the skin, hair, and eyes.
People with albinism often have lighter colored skin and hair than the other members of their family or ethnic group. Vision problems are common.
Melanin normally protects the skin from UV (ultraviolet) damage, so people with albinism are more sensitive to sun exposure. There is an increased risk of skin cancer.
The primary symptoms of albinism can affect the skin, hair, eye color, and vision.
The most obvious sign is a lighter skin tone, but skin tone does not always differ substantially.
In some people, levels of melanin slowly increase over time, darkening skin tone as the person ages.
The skin will likely burn easily in the sun. It does not usually tan.
After exposure to the sun, some people with albinism might develop:
moles, usually pink in color due to the reduced quantities of pigment
lentigines, large freckle-like spots
There is also a higher risk of skin cancer. People with albinism should use sun protection cream of SPF 30 or higher and report any new moles or other skin changes to a doctor.
This can range in color from white to brown. Those of African or Asian descent tend to have yellow, brown, or reddish hair.
As the individual ages, their hair color may slowly darken.
This can also change with age and varies from very light blue to brown.
Low levels of melanin in the iris mean that the eyes can appear slightly translucent and, in certain light, look red or pink as the light reflects off the retina at the back of the eye.
The lack of pigment prevents the iris from fully blocking sunlight. This results in a sensitivity to light, known as photosensitivity.
Albinism always affects vision. Changes to eye function can include:
Nystagmus: The eyes move rapidly and uncontrollably back and forth.
Strabismus: The eyes do not function in unison.Amblyopia: Also referred to as a "lazy eye."
Myopia or hypermetropia: The person may have extreme nearsightedness or farsightedness.Photophobia: The eyes are particularly sensitive to light.
Optic nerve hypoplasia: Visual impairment may result from an underdeveloped optic nerve.
Optic nerve misrouting: Nerve signals from the retina to the brain follow unusual nerve routes.
Astigmatism: An abnormal inflexibility of the front surface of the eye or lens results in blurred vision.
Strategies that may help include:
attaching special telescopic lenses attached to glasses
using a large computer screen or high-contrast print material
installing software that converts text to speech
using a brightly colored ball when playing games
Vision problems related to albinism tend to be worst in newborns but improve rapidly over the first 6 months of life. However, problems with eye health are likely to persist.
Albinism results from a mutation in one of several genes.
One in 70 people are thought to 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.
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, more specific mutations may be discovered, helping us understand the underlying causes of albinism in more detail.
Most types of albinism are inherited in an autosomal recessive inheritance pattern. The exception is X-linked ocular albinism. This is passed on in an X-linked inheritance pattern.
Autosomal recessive inheritance
With autosomal recessive inheritance, an individual must receive faulty copies of a gene from the mother and father to develop albinism.
The parent who carries the gene often does not show symptoms.
If both parents carry the gene but have no symptoms, there is a 1 in 4 chance that their offspring will have albinism.
There is a 1 in 2 chance that the offspring will become a carrier.
They will have the gene but not have any symptoms.
An estimated 1 in 70 people carry the genes associated with albinism but are not affected by the mutations.
X-linked recessive conditions mainly affect males.
Because females carry two X chromosomes, if one gene damaged, the other can often make up the shortfall.
Females can still carry and pass on the gene.
Men, however, have one X and one Y chromosome. This means that any albino mutations in their singular X chromosome will generate the condition.
If the mother has an X-linked mutation, each daughter will have a 1 in 2 chance of becoming a carrier and each son will have a 1 in 2 chance of developing albinism.
The process of diagnosing albinism most often involves:
discussion about skin and hair pigmentation changes
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.
dark glasses to protect the eyes from the sun
regular eye exams
People 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.
Additionally, some people face significant social issues.
These may include bullying at school. The person may be made to 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.
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.