Albinism is a genetic condition which results in a lack of pigmentation in the eyes, skin and hair. It is an inherited condition caused by altered genes being passed on from an individual's parents. Various problems with vision and eyesight can result from the condition.

Lack of Pigmentation

The altered gene which results in albinism prevents the body making the usual amounts of a pigment called melanin. Melanin helps protect the skin from ultraviolet light coming from the Sun. People 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 results in problems with vision, as the eye will not develop properly without the pigment.

Individuals with albinism often have white hair and pale skin which makes them stand out from their families and friends, and from other members of their ethnic group. This can lead to social problems. Growth and development of children with albinism should be normal, however, as should their general health, life span, intelligence, and ability to have children.

Classification

There are two main types of albinism: oculocutaneous albinism (OCA), where melanin pigment is missing in the skin, hair and eyes, and ocular albinism (OA), where the melanin pigment is mainly missing from the eyes, and the skin and hair appear normal. OCA is more common than OA.

Visual Problems Associated with Albinism

People with albinism do not have normal vision. They may have varying degrees of partial-sightedness; either near-sighted or far-sighted. Individuals with these conditions may be helped by the use of glasses, but their vision cannot be corrected completely. Another common condition is nystagmus, an involuntary movement of the eyes back and forth. Using a head tilt or turn may reduce the movement and improve vision.

People with albinism are often sensitive to light, a condition called photo-sensitivity. This is due to the iris allowing stray light to enter the eye. This sensitivity may lead to a dislike of bright lights, but does not prevent people with albinism enjoying the outdoors. As mentioned above, they should avoid prolonged exposure to bright sunlight, as their skin is particularly susceptible to sunburn.

Genetics

Albinism is a genetic condition which is inherited from an individual's parents. For OCA, an individual must inherit an altered albinism gene from both parents. Where an individual receives one albinism gene and one normal gene, that person will not show outward signs of the condition, but will become a carrier. Where two carriers have a child together, that child will have a one in four chance of getting two albinism genes and having albinism. The child will have one in four chances of getting neither albinism gene, having normal pigment, and not being a carrier. The child has two in four chances of getting one normal and one albinism gene, having normal pigment but being a carrier. The incidence of carriers in the British population is approximately 1 in 50.

Albinism affects animals as well as humans. Individuals and animals affected by albinism are known as albinos.

To summarise, the lack of pigmentation which arises from the genetic inheritance of people with albinism can result in various visual problems, but need not prevent individuals leading a healthy, full and active life.

Sources:
http://www.cbc.umn.edu/iac/facts.htm - Facts about albinism
http://www.albinism.org/ - NOAH, the National Organisation for Albinism and Hypopigmentation


My wife has albinism. She suffers from many of the problems mentioned above, including photo-sensitivity, nystagmus, partial-sightedness, and pale skin and hair. She copes very well with these problems on a day-to-day basis, however, and lives an active, normal life.

Some of the tools my wife uses to help her include magnifying tools to help reading (both close-up or far away), sunglasses and hats on bright, sunny days, and a large computer monitor for reading text on her PC. She dislikes crowds, and these are likely to provoke her to use her white stick, whacking anyone who shoves her around! One advantage she has over me is that her partial-sightedness entitles her to a travelcard giving her free rail and bus travel anywhere in Scotland - this sometimes makes me a tad jealous! Elke also dies her hair, eyebrows, and eyelashes in an effort to look as normal as possible and not stand out from the crowd.


Node what you know

Albinism is quite elusive. Once a generic term for anybody who happened to be exceptionally pale, "albino" is now a fairly vague descriptor for an organism with any of several distinct genetic diseases. Scholars have been aware of some types of albinism for at least a few centuries, but relatively little hard research has been performed. Misconceptions abound: many people believe that all albinos possess white skin and hair, red eyes, physical frailty, and occasionally supernatural abilities. In reality, the most universal characteristic of human albinism is poor eyesight— very few albinos can see perfectly, even with corrective lenses— while only a minority have such a severely affected appearance. What follows is a summary of all human knowledge regarding this condition, plus a brief look at how society views it.


Albinism has been observed in a great variety of living things, including mammals, birds, fish, reptiles, amphibians, insects, mollusks, and even plants. It is believed that the disease may occur in any organism that produces pigment, for albinism is broadly defined as any genetic defect that causes a body to produce less pigment than normal.

Pigments are chemicals in a creature's cells that absorb light. Some pigments are photoprotective, meaning that they shield flesh from sunburn by absorbing ultraviolet light. Others perform more subtle functions in the body. For example, melanin, the primary pigment in humans and many other animals, is necessary for some parts of the eye to develop correctly, in addition to its photoprotective role.

The various types of albinism arise from abnormal forms of different, unrelated genes— 100 genes related to albinism have been found in mice. However, all of these genes have one thing in common: they are recessive. This means that although many people are carriers— that is, they possess only one copy of the gene, as 1 in 70 do— a baby must receive two copies of the gene, one from each parent, in order to be born albino. Consequently, there are currently less than 400,000 albino people in the world, including about 18,000 in the United States.

Within the past century, human albinism has been fairly well-classified. Albinism in other animals, though, is still loosely defined. Most animals who have been identified as albino have skin, scales, or feathers that are either totally milk-white or only lack the dark hues of melanin.* How much albinism affects an animal's fitness and thus the process of natural selection is also unclear. Common sense would dictate that without its normal cryptic coloration (colors in an animal's appearance that allow it to camouflage), animals would be easily found and killed by predators. But some predators have been observed as not recognizing an albino as potential food. "In studies where animals had many places to hide, predators captured albino and normally colored animals at the same rate." (Binkley, Susan Kaneko. "Color On, Color Off". Minnesota Conservation Volunteer, Nov-Dec 2001. 28.) In other studies, however, albino birds were less likely to successfully attract mates than their peers. Albinism in plants, meanwhile, is quite rare, since plants require certain pigments in order to perform photosynthesis. Without these pigments, they die.

*Note that some animals, such as polar bears, are naturally white and not albino. Also, some animals have been observed that lack other pigments in addition to melanin. Although they are distinctly different, both of these types of creatures have been described as "leucistic". I have been unable to find an authoritative definition of the term.


Many different types of albinism have been identified in humans. Depending on what type of albinism they have, an albino will suffer from different effects. Not all albinos have all of these symptoms, and severity can differ greatly from person to person.

If an albino's skin and hair are affected by albinism, then the former usually cannot tan, and both will appear lighter than normal for the person's ethnicity. Skin may range from fairly dark to extremely pale, and hair may be brown, red, blonde, totally white, or somewhere in-between. Exceptionally light skin and the inability to tan results in photosensitivity, an increased vulnerability to sunburn. All of these things come directly from a lack of melanin in the affected area.

Every form of albinism affects the eyes to at least some degree. Iris color is caused by the presence of melanin, so the color of the iris is usually blue, gray, or a mix thereof, but it may be brown, especially in more pigmented races. In a few cases, there may be so little melanin in the iris that it becomes translucent or transparent. This makes the blood vessels within the eyeball visible, causing the iris itself to appear red or pink.

Perhaps the most detrimental effect to an albino is handicapped vision. Again, this comes with all forms of albinism. When the eye is growing, it seems to require melanin in order for the fovea and the nerve connections between the retina and brain to develop correctly. In the absence of melanin, these things assume abnormal forms and fail to work as they should. This, in addition to a lack of pigment in the iris, can impair vision in a variety of ways.

An albino's visual acuity can be hampered by near- or far-sightedness, often to greater degrees than normal, or by astigmatism. Astigmatism is a condition in which the lens (part of the eye) does not focus light evenly on the retina, causing the image to be distorted, which results in decreased sharpness of vision. Some (but not all) albinos benefit from wearing glasses or contact lenses. A lucky few of those who do may be able to see perfectly. At the other extreme, an albino's vision may be as poor as 20/400.

Albinism can also cause a number of other, more unusual vision problems. Nystagmus is involuntary movement of the eye, often in a rapid back-and-forth wiggle. The brain can compensate for this to a degree, so that the visual image seems stable, but it may still be somewhat blurry. Strabismus (also known by the names "heterotropia", "wandering eye", and a number of others) is a condition in which the eyes are not coordinated, failing to focus on a single object. This can also impair vision, but, like nystagmus, it may be more of a cosmetic problem in some cases. Finally, photophobia is not a fear of light, as its name suggests, but a sensitivity to light. The lack of pigment in a photophobic albino's eyes allows extra light to leak in, without providing any visual benefit. This means that a photophobe will need to squint in dimmer light than others do.

As of the year 2006, there is no real cure or treatment for albinism, but many of its symptoms can be remedied. Sunscreen can protect against sunburn, hats and sunglasses can aid with photophobia, and magnifiers, corrective lenses, or surgery can help to ameliorate some vision problems.


The exact definition of the word "albinism" has varied wildly over the years, but such change is nothing compared to the state of perpetual flux that the classification of albinism has been in. A number of different schemes have been used for dividing the broad spectrum of albinism into manageable chunks; what I give you here is simply the current one. As our knowledge of albinism specifically and genetics in general grows, it is quite likely that this entire taxonomy will be rendered obsolete and summarily replaced by a whole new system.

Every form of albinism is either oculocutaneous or ocular. Oculocutaneous albinism (OCA) affects the skin, hair, and eyes, while ocular albinism (OA) affects the eyes alone. OCA, which is more common, can be further divided into subgroups that distinguish between the different possible genetic origins of the condition. Tyrosinase-related oculocutaneous albinism, or oculocutaneous albinism type I (OCA1), results from a defective gene that governs the production and activities of tyrosinase, an enzyme necessary for the creation of melanin. Most people with OCA1 are born with very pale skin, white hair, and blue eyes.

OCA1 itself also comes in two different varieties. Type A (OCA1A) is the only real form of albinism that bears much resemblance to albinism as it appears in popular mythology. Its particular effects are due to a null mutation of the tyrosinase gene, meaning that the body doesn't produce any tyrosinase at all, or what tyrosinase is produced completely fails to function. Consequently, OCA1A is one of the most severe forms of albinism; those who have it are marked by completely unpigmented features, and vision typically ranges from 20/200 to 20/400. Photophobia and nystagmus are especially problematic for those afflicted with OCA1A, and corrective lenses often don't help. The phenotype of OCA1A (that is, the way a person's gene for OCA1A is expressed) is the same regardless of ethnicity.

Oculocutaneous albinism type IIB (OCA1B) is the product of a leaky mutation of the gene, meaning that some tyrosinase is produced and it operates at some level of activity, usually around 1 to 10 percent of normal. Those with OCA1B are all born with little to no pigmentation, but this may change over the first two decades of life as the body slowly produces melanin, resulting in darker skin, hair, and eye colors along with improved vision. (The hair always darkens a little at first, and sometimes it may progress to a dark blonde or brown in adolescence or early adulthood.) The (uncorrected) visual acuity of a person with OCA1B can be as high as 20/90 or as low as 20/400. The OCA1B phenotype, unlike that of OCA1A, is influenced by normal ethnic and familial pigmentation. (Incidentally, OCA1B is also the form of albinism I have diagnosed myself with.)

The other main type of OCA, and the most common single form of albinism in the world, is P gene-related oculocutaneous albinism, or oculocutaneous albinism type II (OCA2). As its full name suggests, OCA2 has something to do with a gene called the P gene; unfortunately, I haven't been able to deduce exactly what the P gene is— I assume it has something to do with the production of melanin. OCA2 is like OCA1B, in that the phenotype can vary greatly and is dependent on ethnicity, but there are a few salient differences. Firstly, most of those with OCA2 have some pigmentation in the hair and eyes at birth; secondly, the hair cannot darken with age as much as it can in OCA1B.

Another, less common type of OCA is brown OCA. So far, it has only been observed in Africans and African-Americans. It, too, stems from a mutation in the P gene; some hypothesize that OCA2 comes from a null mutation of the gene and brown OCA from a leaky one. People with brown OCA are born with light-brown skin, and irises of a hue ranging from gray to tan. The hair and eyes may darken with age, but the skin never does. Vision lies between 20/60 and 20/150.

OA is much less common than OCA. It was once diagnosed more frequently, but many of those who were said to have OA turned out to actually have OCA1B or OCA2 with very little pigmentation in the skin and hair. Now, scientists acknowledge only one type of true OA, X-linked ocular albinism, or ocular albinism type I (OA1). The gene that causes OA1 lies on the X chromosome— which, because of the logistics of gene expression, means that more males will exhibit the condition than females. The skin and hair of people with OA1 is normal or nearly normal, while the eyes may appear normal, but vision is always affected; its acuity ranges from 20/50 to 20/400.

There are also a number of very special cases of albinism, along with other diseases that include albinism or hypopigmentation among their effects, such as Prader-Willi, Angelman, Hermansky-Pudlak, and Chediak-Higashi syndromes. These are, generally speaking, rather severe conditions, and a lack of melanin is probably benign compared to their more serious mental or life-threatening symptoms.


In the first third of his most famous work, Moby-Dick, American author Herman Melville devotes an entire chapter to describing the titular whale's skin color. The deathly pale hue of Moby Dick's flesh, Melville asserts, makes the beast uniquely terrible to behold. To illustrate his point, he cites examples of other white animals, including albino humans:

What is it that in the Albino man so peculiarly repels and often shocks the eye, as that sometimes he is loathed by his own kith and kin! It is that whiteness which invests him, a thing expressed by the name he bears. The Albino is as well made as other men—has no substantive deformity—and yet this mere aspect of all-pervading whiteness makes him more strangely hideous than the ugliest abortion.
The truth is, whatever the exact cause, pale albinos have frightened and puzzled people for centuries. It is unsurprising, then, that they have received unusual and often negative treatment, in real life as well as fiction.

Misconceptions about albinism abound. Many people believe that all albinos are as pale as those with OCA1A, have red or pink eyes but perfect vision, are physically frail, or have magical powers. Even today, there is a myth in Zimbabwe that a man with HIV can cure it by having sex with an albino woman— this has occasionally been a motive for rape. (Unsurprisingly, albinos tend to be treated worse in countries where the average skin color is darker.)

Fictional depictions of albinism tend to be both degrading and inaccurate. There are a number of albino or otherwise exceptionally pale villains in film, such as the Twins from The Matrix Reloaded and the Morlocks in The Time Machine. In literature, there is Elric of Melniboné, from the series of the same name by Michael Moorcock. Though Elric is the protagonist of the books in which he appears and Moorcock describes him as "beautiful", he is also cruel and vengeful and too frail to live without magical aid.

One exception to this negative trend is Balder, a blond-haired, blue-eyed deity from Norse mythology. Balder is loved by almost all the gods and giants, and his murder by the treacherous god Loki, through a chain of events, ends up bringing about the end of the world. He is later released from the underworld to become one of only a few gods to survive the apocalypse.


As far as diseases go, albinism is relatively harmless. It is not very common, and in most cases it is not very severe. Still, it is worth further research— not only to help find a treatment or cure for human albinism, but also to better understand genetics, evolution, and sociology by using albinism as a model. Until then, albinos are stuck living in a pigmented world.


Bibliography

Binkley, Susan Kaneko. "Color On, Color Off". Minnesota Conservation Volunteer, Nov-Dec 2001. Minnesota Department of Natural Resources. Retrieved 14 Jan 2006 from:
http://files.dnr.state.mn.us/publications/volunteer/young_naturalists/albino_animals/albino_animals.pdf

King, Richard A., et. al. "Facts About Albinism". International Albinism Center at the University of Minnesota. Retrieved 14 Jan 2006 from:
http://albinism.med.umn.edu/facts.htm

Wikipedia contributors. "Albinism" and "Strabismus". Wikipedia, The Free Encyclopedia. Retrieved 14 Jan 2006 from:
http://en.wikipedia.org/w/index.php?title=Albinism&oldid=34681141
http://en.wikipedia.org/w/index.php?title=Strabismus&oldid=34047085

Zasada, John. "Albino Plants". Geophysical Institute, University of Alaska Fairbanks, 6 Oct 1980. Retrieved 14 Jan 2006 from:
http://www.gi.alaska.edu/ScienceForum/ASF4/433.html

Al"bi*nism (#), n.

The state or condition of being an albino: abinoism; leucopathy.

 

© Webster 1913.

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