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![]() White Diamond Albinism |
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The word "albinism" refers to a group of inherited conditions. People with albinism have little or no pigment in their
eyes, skin, or hair. They have inherited genes that do not make the usual amounts of a pigment called melanin. One person in 17,000 in the U.S.A. has some type of albinism. Albinism affects people from all races. Most children with
albinism are born to parents who have normal hair and eye color for their ethnic backgrounds. Often people do not recognize
that they have albinism. A common myth is that by definition people with albinism have red eyes. In fact there are different types of albinism,
and the amount of pigment in the eyes varies. Although some individuals with albinism have reddish or violet eyes, most have
blue eyes. Some have hazel or brown eyes. People with albinism always have problems with vision, and many have low vision. Many are "legally blind," but most use
their vision for reading, and do not use braille. Some have vision good enough to drive a car. Vision problems in albinism result from abnormal development of the retina and abnormal patterns of nerve connections between
the eye and the brain. It is the presence of these eye problems that defines the diagnosis of albinism. Therefore the main
test for albinism is simply an eye exam. While most people with albinism have very light skin and hair, not all do. Oculocutaneous (pronounced Ock-you-low-kew-Tain-ee-us)
albinism involves the eyes, hair, and skin. Ocular albinism involves primarily the eyes, while skin and hair may appear similar
or slightly lighter than that of other family members. Over the years researchers have used various systems for classifying oculocutaneous albinism. In general, these systems
contrasted types of albinism having almost no pigmentation with types having slight pigmentation. In less pigmented types
of albinism, hair and skin are cream-colored, and vision is often in the range of 20/200. In types with slight pigmentation,
hair appears more yellow or red-tinged, and vision often corrects to 20/60. Early descriptions of albinism called these main
categories of albinism "complete" and "incomplete" albinism. Later researchers used a test that involved plucking a hair root,
and seeing if it would make pigment in a test tube. This test separated "ty-neg" (no pigment) from "ty-pos" (some pigment).
Further research showed that this test was inconsistent, and added little information to the clinical exam. Recent research has used analysis of DNA, the
chemical which encodes genetic information, to arrive at a more firm classification system for albinism. Type 1 albinism (also
called tyrosinase-related albinism) is the type involving almost no pigmentation. Type 1 albinism results from a genetic defect
in an enzyme called tyrosinase. This enzyme helps the body to change the amino acid tyrosine into pigment. (An amino acid
is a "building block" of protein, and comes from protein in the diet.) Type 2, a type with slight pigmentation, results from
a defect in a different gene called the "P" gene. Researchers have identified several other genes that cause forms of albinism. In one form of albinism, the Hermansky-Pudlak
syndrome, there can be problems with bleeding, and with lung and bowel disease as well. Hermansky-Pudlak syndrome is a less
common form of albinism, but should be suspected if a child with albinism shows unusual bruising or bleeding. For nearly all types of albinism both parents must carry an albinism gene to have a child with albinism. Because the body
has two sets of genes,a person may have normal pigmentation but carry the albinism gene. If a person has one gene for normal
pigmentation and one gene for albinism, he or she will have enough genetic information to make normal pigment. The albinism
gene is "recessive" — it does not result in albinism unless a person has two copies of the gene for albinism and no
copy of the gene that makes normal pigment. When both parents carry the gene, and neither parent has albinism, there is a one in four chance at each pregnancy that
the baby will be born with albinism. This type of inheritance is called autosomal recessive inheritance. (The most common type of ocular albinism follows a different pattern of inheritance. The NOAH Information Bulletin "Ocular
Albinism" has more information.) Each parent of a child with oculocutaneous albinism must carry the gene. Both the father and the mother must carry the
gene for albinism. For couples who have not had a child with albinism, there is no simple test to determine whether a person
carries a gene for albinism. Researchers have analyzed DNA
of people with albinism and found the changes that cause albinism, but these changes are not always in exactly the same place,
even for a given type of albinism. Therefore the tests for the gene may be inconclusive. If parents have had a child with albinism previously, there is a way to test in subsequent pregnancies to see if the fetus
has albinism. The test uses amniocentesis (placing a needle into the uterus to draw off fluid). Cells in the fluid are examined
to see if they have an albinism gene from each parent. For specific information and genetics and testing, seek the advice of a qualified genetic counselor. Genetic counselors
are usually associated with universities and children's hospitals. The National Society of Genetic Counselors at (610) 872-7608
in Philadelphia maintains a referral list. Those considering prenatal testing should be made aware that people with albinism can adapt well to their disabilities,
and lead fulfilling lives. Vision Rehabilitation: Eye conditions common in albinism include These eye problems result from abnormal development of the eye because of lack of pigment. The retina, the surface inside
the eye that receives light, does not develop normally before birth and in infancy. The nerve signals from the retina to the
brain do not follow the usual nerve routes. 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.) 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). People with albinism are sensitive to glare, but they do not prefer to be in the dark, and need light to see just like
anyone else. Sunglasses or tinted contact lenses help outdoors. Indoors, it is important to place lights for reading or close
work over a shoulder rather than in front. Various optical aids are helpful to people with albinism, and the choice of an optical aid depends on how a person uses
his or her eyes in jobs, hobbies, or other usual activities. 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 one 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.) 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. In the United States, people with albinism live normal life spans and have the same types of general medical problems as
the rest of the population. The lives of people with Hernansky-Pudlak syndrome can be shortened by lung disease or other problems.
In tropical countries, those who do not use skin protection may develop life-threatening skin cancers. If they use appropriate
skin protection, such as sunscreen lotions rated 20 or higher, and opaque clothing, people with albinism can enjoy outdoor
activities even in summer. People with albinism are at risk of isolation, because the condition is often misunderstood. Social stigmatization can
occur, especially within communities of color, where the race or paternity of a person with albinism may be questioned. Families
and schools must make an effort not to exclude children with albinism from group activities. Contact with others with albinism or who have albinism in their families is most helpful. NOAH can provide the names of
contacts in many regions of the country. This article with many others can be found on the NOAH website at http://www.albinism.org/
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whitediamond@whitediamondrap.com White Diamond |
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