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 genes passed from both parents of an individual. This condition is known to affect mammals, fish, birds, reptiles, and amphibians.
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.
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, for example nystagmus (involuntary eye movement) and in around 25% of cases ONH (Optic Nerve Hypoplasia).
There are two main categories of albinism in humans: oculocutaneous and ocular. In ocular albinism, only the eye lacks 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. Also, some people with albinism may have Hermansky-Pudlak Syndrome, which is most prominent in the Puerto Rican population, where the frequency is about 1:1,800. In many organisms, the eyes of a person with albinism appear red due to the underlying blood vessels showing through where there is not enough pigment to cover them. In humans this is generally not the case, as a human eye is quite large and thus produces enough pigment to lend opacity to the eye. Despite this, completely red eyes resulting from a lack of melanin to cover the underlying blood vessels are not unknown in humans.
Vision aside, people with albinism are generally as healthy as the rest of their species, with growth and development occurring as normal. Many organisms, however, lose their protective camouflage and are unable to conceal themselves from their predators or prey. The survivability rate of albino animals 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 albino offspring resulting from the pairing of an albino with a non-albino is very low and is discussed below.
Visual problems associated with albinism
People with albinism always suffer from impaired vision. While an albino may suffer from a standard eye affliction (astigmatism, near-sightedness, etc), the general 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 non-albinos, one can imagine it as seeing at a lower resolution. Additionally, most albinos suffer nystagmus (a rapid, involuntary "shaking" of the eyes).
Individuals with these conditions may be helped by the use of glasses and low-visual aids such as magnifiers, as well as bright but angled reading lights, but their vision cannot be corrected completely. Although surgery is possible on the ocular muscles, effectively simulating (to a limited degree) the improvements in the albino's vision that often come with age, the gain is generally thought to be out-weighed by the trauma.
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. They should avoid prolonged exposure to bright sunlight regardless, as their skin is particularly susceptible to sunburn.
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 albinos.
Zimbabwe, currently under the strain of an HIV epidemic, has developed a myth that sleeping with an albino woman will cure a man of the disease. This has led to many albino and some white women in the area being raped.
In Jamaica, albinos have long been denigrated and regarded as cursed. In recent times, the albino dancehall singer Yellowman has helped to end this negative stereotype.
In 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, Bran Davies from The Dark is Rising book series by Susan Cooper, Silas in Dan Brown's The Da Vinci Code and in H. G. Wells' The Invisible Man, the titular character was born an albino.
Albinos are often the target of insensitive jokes in Western culture. For example, the movie Me, Myself and Irene featured an albino character 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.
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.
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 albinos
- 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
- Edgar Winter: American rock musician
- Johnny Winter: American blues musician
- Tony Evans: American newspaper columnist
- Brother Ali : American hip hop MC
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
- The UK Albinism Fellowship
- NOAH The National Organization for Albinism and Hypopigmentation US
- 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*
- Albino Animals - Albino and white mammals and birds
- Albino frogs
- Albino Tiger Barb
- Albino Corydorus paleatus
- Pale Riders Who Wear Black Hats - Wired News article on albinism in cinema
- [1] - Albino portraits by Pieter Hugo