The condition affects an estimated 1 in 17,000 people globally. However, its prevalence varies by region.
In sub-Saharan Africa, the rate of albinism is around 1 in 5,000 but, in Europe and America, it is closer to 1 in 20,000.
Albinism affects the sexes evenly, and all ethnic groups are susceptible.
Contents of this article:
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 disorder
- 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.
In general, but not always, people with albinism have lighter colored skin and hair than the other members of their family or ethnic group.
Regardless of skin or hair tone, people with albinism always have some level of dysfunction with their vision.
Because melanin normally protects the skin from UV (ultraviolet) damage, people with the disorder are more sensitive to sun exposure and have an increased risk of skin cancer.
Symptoms of albinism
Albinism is a genetic disorder affecting roughly 1 in 17,000 people.
The primary symptoms of albinism can be split into the following four categories:
Skin: the most obvious symptom of albinism is a lighter skin tone. However, skin tone does not always differ substantially. Levels of melanin may slowly increase in some individuals, slowly darkening their skin tone as they age.
After exposure to the sun, some people with albinism might develop freckles, moles (generally pink in color due to the reduced quantities of pigment), and large freckle-like spots called lentigines.
Hair: as with skin, the hair 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.
Eye color: 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 makes people with albinism sensitive to light (photosensitive).
Vision: vision is always affected by albinism. Changes to eye function can include:
- Nystagmus - eyes move rapidly and uncontrollably back and forth
- Strabismus - the eyes do not function in unison
- Amblyopia - also referred to as a "lazy eye"
- Extreme nearsightedness or farsightedness
- Optic nerve hypoplasia - underdeveloped optic nerve
- Optic nerve misrouting - nerve signals from the retina to the brain follow unusual nerve routes
- Astigmatism - abnormal inflexibility of the front surface of the eye or lens causing blurred vision.
Vision problems related to albinism tend to be worst in newborns but improve rapidly over the first 6 months of life; however, they do not tend to reach normal levels of eye health.
Causes of albinism
Family with albinism begging in India.
Albinism is caused by a mutation in one of several genes. 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) which synthesizes melanin from the amino acid tyrosine.
Depending on the mutation, melanin production can either be slowed or completely stopped. But, regardless of the amount of interference with melanin production, there are always associated problems with the visual system in albinism.
These vision problems occur because of melanin's 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. These subgroups include the following:
Oculocutaneous albinism (OCA): 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: similar to type 1 and occurs most often in sub-Saharan Africans, African-Americans, and Native Americans.
- OCA type 3: occurs mostly in black South Africans.
- OCA type 4: occurs most often in East Asian populations.
- X-linked ocular albinism: caused by a gene mutation of the X chromosome, X-linked ocular albinism occurs predominantly in 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 patients are more likely to develop bowel, heart, kidney, and lung diseases or bleeding disorders, such as hemophilia.
- Chediak-Higashi syndrome: 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 skin can look slightly gray. These individuals also have defects in their white blood cells, making infections more common.
As research continues, no doubt more specific mutations will be discovered, helping us understand the genesis of albinism in increasing detail.
Inheritance of albinism
Most types of albinism are inherited in an autosomal recessive inheritance pattern, the exception being X-linked ocular albinism which is passed on in an X-linked inheritance pattern.
Autosomal recessive inheritance
Holy Indian sadhu with albinism.
With autosomal recessive inheritance, an individual must receive faulty copies of a gene from the mother and father to develop albinism.
If both parents carry the gene, there is a 1 in 4 chance that their offspring will have albinism and a 1 in 2 chance that the offspring will become a carrier (without symptoms).
An estimated 1 in 70 people carry the genes associated with albinism but are not affected by the mutations.
X-linked recessive conditions predominantly 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, so 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.
Diagnosis of albinism
The process of diagnosing albinism most often involves:
- Physical exam
- Discussion about skin and hair pigmentation changes
- Examination of the eyes by an expert (ophthalmologist)
- Comparing the individual's coloration to 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, if there is a history of albinism within the family, this is not always deemed necessary.
Treatment for albinism
Because the disease is genetic, there are no cures; treatment revolves around minimizing the symptoms and watching for changes.
Getting the right care for eye problems is essential, including prescription glasses, dark glasses to protect the eyes from the sun, and regular eye exams. It is also important to watch the skin for changes and to use sunblock for protection.
Surgery on the optical muscles can sometimes minimize the "shaking" in nystagmus. Similarly, operations to minimize strabismus can make it less noticeable. The surgery does not improve vision, however, and the level of success in reducing symptoms varies from individual to individual.
Albinism does not get worse with age, and a child with albinism is able to flourish and achieve the same education and employment as a person without the condition.
Complications of albinism
The most common physical problems associated with albinism are the increased risk of sunburn and skin cancers.
Additionally, people with albinism can face significant social issues.
Because they look different, they may be bullied at school or feel like an outsider because they do not "fit in" with the rest of their family or ethnic group.
People with albinism in sub-Saharan Africa face the greatest challenges.
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."
Worse still, in some sub-Saharan countries such as Tanzania and Burundi, the body parts of individuals with albinism are sought after by witch doctors.
In some African countries, Tanzania and Zimbabwe particularly, it is believed that having sex with a woman with albinism cures AIDS (acquired immune deficiency syndrome). This false belief has led to murder, rape, and additional AIDS infections.