Albinism in humans
| Albinism in humans |
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Albinism (from Latin albus, meaning "white") is a lack of pigmentation in the eyes, skin and hair. It is an inherited condition resulting from the combination of recessive alleles passed from both parents of an individual. This condition is known to affect mammals, fish, birds, reptiles, and amphibians. While the most common term for an individual affected by albinism is "albino", most of them prefer "person with albinism", because "albino" is most often used in a derogatory way.
Genetics
The gene which results in albinism prevents the body from making the usual amounts of a pigment called melanin. Albinism used to be categorised as Tyrosinase positive or negative. In cases of Tyrosinase positive albinism, the enzyme tyrosinase is present but is unable to enter pigment cells to produce melanin. In tyrosinase negative cases, this enzyme is not produced. This classification has been rendered obsolete by recent research.
About 1 in 17,000 people have some type of albinism, although up to 1 in 70 are carriers.
There are many genes which are now scientifically proven to be associated with albinism (or better: alterations of the genes). All alterations, however, lead to an alteration of the melanin (pigment/coloring) production in the body. Melanin helps protect the skin from ultraviolet light coming from the sun (see human skin color for more information). Organisms with albinism lack this protective pigment in their skin, and can burn easily from exposure to the sun as a result. Lack of melanin in the eye also results in problems with vision unrelated to photosensitivity, which are discussed further below.
There are two main categories of albinism in humans: oculocutaneous and ocular. In ocular albinism, only the eyes lack pigment. In oculocutaneous pigment is missing from the hair, eyes, and skin. People who have ocular albinism have normal skin/hair color and many have normal eye color. People with oculocutaneous albinism can have no pigment to almost normal. Some may even tan.
The eyes of a person with albinism often appear red due to the underlying blood vessels showing through where there is not enough pigment to cover them. In humans this is rarely the case, as a human eye is quite large and thus produces enough pigment to lend opacity to the eye. However, there are cases in which the eyes appear red or purple, depending on the amount of pigment present.
Vision aside, people with albinism are generally as healthy as the rest of their species, with growth and development occurring as normal. Many animals with albinism, however, lose their protective camouflage and are unable to conceal themselves from their predators or prey. The survivability rate of animals with albinism in the wild is usually quite low. The largest problem people with albinism face is social, as the condition usually is a source of torment during adolescent years.
As albinism is a recessive gene, the chance of offspring with albinism resulting from the pairing of someone/thing with albinism with something/one without albinism is very low and is discussed below.
Types of albinism
There are many types of albinism. While there is only one type of ocular albinism, there are at least five types of oculocutaneous albinism, one of which has several subtypes. Some are easily distinguished by appearance, but in most cases, genetic testing is the only way to be sure. Apart from HPS (see below) testing has no medical benefits.
- The type with the usually least amount of pigment is OCA1 (Online Mendelian Inheritance in Man (OMIM): 203100). People with this type usually have very white skin, white hair and light blue eyes, although some have red or purple eyes. OCA1 is caused by an alteration of the tyrosinase gene, and can occur in two variations. The first is OCA1A, and means that the organism cannot develop pigment at all. Vision usually ranges from 20/200 to 20/400. The second is OCA1b, which has several subtypes itself. Many individuals with OCA1b can tan and develop pigment during their lives. One subtype of OCA1b is called OCA1b TS (Temperature Sensitive), where the tyrosinase can only function below a certain temperature, which causes the body hair in cooler body regions to develop pigment (i.e. get darker).
- The most common type of albinism is OCA2 (Online Mendelian Inheritance in Man (OMIM): 203200), which is caused by alterations of the P-gene. People with OCA2 generally have more pigment, and better vision than those with OCA1, but cannot tan like some with OCA1b. A little pigment can develop in freckles or moles. People with OCA2 usually have fair skin but not as white as OCA1, and light to golden or reddish blonde hair, and usually blue eyes. Affected people of African decent usually have a different phenotype (appearance): Yellow hair, rather white skin and blue, gray or hazel eyes.
- OCA3 or Rufuous (=Red) Albinism (Online Mendelian Inheritance in Man (OMIM): 203290) has only been partially researched and documented. Cases have been reported in Africa and New Guinea, affected individuals have red hair and reddish brown skin and blue or gray eyes.
- HPS or Hermansky-Pudlak-Syndrome (Online Mendelian Inheritance in Man (OMIM): 203300) is not a type of OCA itself, but has similar features. HPS has a great range of degrees of pigmentation, from OCA1A-like to almost normal. Vision usually ranges from 20/60 to 20/200. Apart from the hypopigmentation and impaired vision, people with HPS have an abnormality in their blood platelets, which usually leads to bleeding issues and bruising easily, and people with HPS often suffer from lung fibrosis (scarring of the lung) and other sicknesses. HPS is very rare, only in the Puerto Rican population its occurence is 1 in 1,800.
- Ocular albinism (OA1) (Online Mendelian Inheritance in Man (OMIM): 300500) affects only the eyes, and occurs primarily in males, as it is X-linked inherited. Nonetheless, skin color can be slightly lighter than those of the rest of the family, or "normal". The eye color can vary greatly, in which case only examination of the retina can reveal OA1.
Visual problems associated with albinism
People with albinism always suffer from impaired vision, but the degree varies greatly. While a person with albinism may suffer from a standard eye affliction like near-sightedness or far-sightedness, the biggest problem arises from a poorly-developed retina and abnormal nerve connections between the eyes and brain. It should be noted that it is the presence of these abnormalities that medically define albinism. While the actual effects of this condition are generally difficult to describe to pigmentos, one can imagine it as seeing at a lower resolution. Additionally, most people with albinism suffer nystagmus (a rapid, involuntary "shaking" of the eyes) which further reduces vision. People with albinism are also likely to have astigmatism or strabismus.
The lack of pigment in the eye generally leads to ocular photophobia or hyper-photo-sensitivity. This is due not so much to the iris allowing stray light to enter the eye, as to a lack of pigment within the eye, allowing light to refract within the eyeball. A good analogy would be taking a picture with a film camera that is painted white within, rather than black. Such sensitivity generally leads to a dislike of bright lights, but does not prevent people with albinism enjoying the outdoors, especially when using sunglasses and/or hats. They should avoid prolonged exposure to bright sunlight regardless, as their skin is particularly susceptible to sunburn.
Sun Protection and Vision Aids
Albinism is a condition that cannot be "cured" or "treated" per se, but many little things can be done to improve the quality of life for those affected. It is vital that people with albinism use sunscreen when exposed to sunlight to prevent premature skin aging or skin cancer. This poses a big problem for those who cannot afford sunscreen, especially in countries with high exposure to sunlight, like on the African continent. Special UV-proof clothing and swimsuits are available and are a good alternative to excessive use of sunscreen.
Glasses and low-visual aids such as magnifiers, large print materials or CCTVs (closed-circuit television), as well as bright but angled reading lights can help individuals with albinsim, even if their vision cannot be corrected completely. Although still disputed among the experts, many ophthalmologists recommend the use of glasses from early childhood on to allow the eyes the best development possible. Surgery is possible on the ocular muscles to decrease nystagmus, strabismus and common refractive errors, but especially with nystagmus surgery the effectiveness varies greatly and depends on individual circumstances. It remains to be seen if further improvements allow for better correction in the future.
Use of sunglasses and hats with wide brims can make the glare outside bearable. Other things that can help people with albinism are avoiding sudden changes of the lighting situation (switching the light on in complete darkness), use dimmable switches, add tint to car windows or blinds to normal windows. Lights should be yellowish rather than blue and not point towards the usual position of a person with albinism (like their seat at a table). When possible, people with albinism prefer to have the light on their backs rather than face it.
Culture
Myths and Superstitions
Due to albinism's effect on one's outward appearance, cultures around the world have developed many myths and superstitions regarding people with albinism.
Zimbabwe, currently under the strain of an HIV epidemic, has developed a myth that sleeping with a woman with albinism will cure a man of the disease. This has led to many women with albinism and even some white women without albinsim in the area being raped.
In Jamaica, Africa, people with albinism have been degraded and regarded as cursed. In recent times, the affected dancehall singer Yellowman has helped to end this negative stereotype.
In some cultures, people with albinism are thought to have magical powers or are able to tell the future.
In the Media
Albino bias is prevalent in Western media. Several works of fiction have featured evil pale-skinned, platinum-blonde characters, including Michael Moorcock's Elric, The Twins from The Matrix Reloaded, Silas in Dan Brown's The Da Vinci Code, and Draco Malfoy in the Harry Potter book series, and in H. G. Wells' The Invisible Man, the titular character had albinism.
People with albinism are often the target of insensitive jokes in Western culture. For example, the movie Me, Myself and Irene featured a character with albinism who was referred to by the nickname "Whitey", and was used as the butt of several jokes. Several cheap jokes have also been made on The Simpsons, with Homer calling Edgar Winter and his brother Johnny a couple of "chalk-faced goons" and running them over with a hearse. Interestingly, people with albinism have perfect vision in the movies, regarding how often they are portrayed as snipers or driving cars etc. It shows how little effort is made to research the condition.
Other
Bristol Zoo was the home to a very rare albino African penguin named Snowdrop. Snowdrop was hatched at the zoo in October 2002 and died in August 2004. For many years, a unique albino gorilla named Floquet de Neu (Snowflake) was the most famous resident of the Parc Zoològic de Barcelona. An albino humpback whale travels up and down the east coast of Australia, and has become famous in the local media. The whale is called Migaloo (the Aboriginal word for "white lad").
Medical science and toxicology, for better or worse, often take advantage of the standardized lack of pigment in albino animals in testing for materials' chemical properties. An example of such a test is the test for corrosiveness, which is a skin exposure test performed on albino rabbits.
Famous people with albinism
- Pierre Bourgault: Québécois politician
- Cano Estremera: Puerto Rican salsa musician
- Li Yipeng, Lee Hsien Loong's son
- Stanley Kaoni: Solomon Islander militant leader
- Salif Keita: Malian popular musician
- Hermeto Pascoal: Brazilian jazz musician
- Piano Red: American blues musician
- Nestor Sánchez: Cuban singer
- William Archibald Spooner: Anglican priest
- Yellowman: Jamaican dancehall musician
- Al beeno: Jamaican dancehall musician
- Edgar Winter: American rock musician
- Johnny Winter: American blues musician
- Tony Evans: American newspaper columnist
- Brother Ali : American hip hop MC
- Heino : German singer
- Connie Chiu : Photo model for Jean-Paul Gaultier
See also
- vitiligo (or leukoderma), the patchy loss of skin pigmentation
- melanosis, the condition of having too much skin pigmentation
Publications
- Albino Animals by Kelly Milner Halls. Darby Creek Publishing (March, 2004) ISBN 1581960123
External links
Albinism in humans:
- The UK Albinism Fellowship
- NOAH The National Organization for Albinism and Hypopigmentation USA
- Albinism International Online Support Community for people with albinism and their family members
- Albinism in Popular Culture
- Biblical references - William Blake's Ancient of Days was based upon the Revelation of St John the Divine, 1:14: *:"His head and hair were white like wool, as white as snow, and His eyes like a flame of fire*
- Pale Riders Who Wear Black Hats - Wired News article on albinism in cinema
- Portraits of People with albinism by Pieter Hugo
Albinism in animals:
- Albino Animals - Albino and white mammals and birds
- Albino frogs
- Albino Tiger Barb
- Albino Corydorus paleatus