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Albinism

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"Albino" redirects here. For , see .
The Wonderful Albino Family. Currier & Ives lithograph of Rudolph Lucasie, his wife and children
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The Wonderful Albino Family. Currier & Ives lithograph of Rudolph Lucasie, his wife and children

Albinism (from Latin albus, meaning "white") is a lack of pigmentation in the eyes, skin and hair. Albinism 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", some prefer "person with albinism", because "albino" is sometimes used in a derogatory way. The gene which results in albinism prevents the body from making the usual amounts of the pigment 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 75 are carriers.

There are many alterations of genes which are proven to be associated with albinism. 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 oculocutaneous albinism, pigment is missing from the hair, eyes, and skin. In ocular albinism, only the eyes lack pigment. People with oculocutaneous albinism can have no pigment to almost normal. Some may even tan. People who have ocular albinism have normal skin/hair color and many have normal eye color.

The eyes of a person with albinism occasionally 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.

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 is sometimes a source of teasing during adolescent years.

As albinism is a recessive gene, the chance of offspring with albinism resulting from the pairing of a creature with albinism with a creature without albinism is very low and is discussed below.

Contents

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.









Visual problems associated with albinism

Eye conditions common in albinism may include (for all will not necessarily be present):




People with albinism 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. These abnormalities define albinism, medically. While the  effects of this condition are difficult to describe, it can be explained as seeing at a lower resolution.  Additionally, most people with albinism suffer from nystagmus (a rapid, involuntary "shaking" of the eyes) which further reduces vision. People with albinism are also likely to have astigmatism or strabismus. 


The iris, the colored area in the center of the eye, does not have enough pigment to screen out stray light coming into the eye. Light normally enters the eye only through the pupil, the dark opening in the center of the iris, but in albinism light can pass through the iris as well. 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 (see below).



Sun protection and vision aids



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Albinism is a condition that cannot be "cured" or "treated" per se, but small 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 problem for those who cannot afford sunscreen, especially in countries with high exposure to sunlight, as in Africa. Special UV-proof clothing and swimsuits are available and are a good alternative to excessive use of sunscreen.


For the most part, treatment of the eye conditions consists of visual rehabilitation. Surgery to correct strabismus may improve the appearance of the eyes. However, since surgery will not correct the misrouting of nerves from the eyes to the brain, surgery will not provide fine binocular vision. In the case of esotropia or "crossed eyes," surgery may help vision by expanding the visual field (the area that the eyes can see while looking at one point).  Nystagmus damping surgery can also be performed, to reduce the "shaking" of the eyes back and forth.


Glasses and low-visual aids such as magnifiers, large print materials or closed captioning, as well as bright but angled reading lights can help individuals with albinism, even if their vision cannot be corrected completely. Some people do well using bifocals which have a strong reading lens, prescription reading glasses, or contact lenses. Others use hand-held magnifiers or special small telescopes. Some use bioptics, glasses which have small telescopes mounted on, in, or behind their regular lenses, so that they can look through either the regular lens or the telescope. Newer designs of bioptics use smaller light-weight lenses. Some states allow the use of bioptic telescopes for driving. (See also NOAH bulletin "Low Vision Aids".)  


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.


Optometrists or ophthalmologists who are experienced in working with low vision patients can recommend various optical aids. Clinics should provide aids on trial loan, and provide instruction in their use. The American Foundation for the Blind (1-800-AFB-LIND) maintains a directory of low vision clinics.


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), using dimmable switches and adding 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 generally prefer to have the light on their backs rather than face it.



Culture


Under the Spanish casta, albino (or albina, if female) was the term used to categorize an individual who was one-eighth African and seven-eighths Spanish.



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.


A common misconception is that albino individuals of a species are sterile, but albinos are fully capable of reproducing.


A myth has developed in Zimbabwe that having sex with a woman with albinism will cure a man of HIV. This has led to many women with albinism in the area being raped [ipsnews.net].


In Jamaica, West Indies, people with albinism have been degraded and regarded as cursed.  In recent times, the albino dancehall singer Yellowman has helped to end this stereotype.


In some cultures, people with albinism are thought to have magical powers, or are able to tell the future.


It is also thought by many that people with albinism live short life spans.  This is not true, but may be a distorted view of a more reasonable fact that people with albinism have a higher risk of skin cancer if they do not use proper skin protection  when in the sun.



Snowdrop, an albino African Penguin, born at Bristol Zoo (England), died in August 2004. Snowdrop would normally have looked like the background penguins

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Snowdrop, an albino African Penguin, born at Bristol Zoo (England), died in August 2004. Snowdrop would normally have looked like the background penguins








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 can 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.


The 2004 book Weird U.S. chronicled (and further popularized) one of the lesser known "local myths" of the country, Albino Colonies. The book uses firsthand accounts mailed to the authors to paint a picture of various locations in the U.S. (most notably Clifton, New Jersey) where colonies of albino families and neighbors live in seclusion. The accounts tell tales of honking horns to try to bring the albinos out of their houses, being shot at with rock salt by albinos, and even vigilantism by gangs of albinos.



Famous people with albinism



See also



References








External links






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