ALBINISM SYMPTOMS |
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Every cell in the body contains a
matched pair of genes, one inherited from each parent. These genes
act as a sort of "blueprint" that guides the development of a fetus.
Albinism is an inherited problem caused by a flaw in one or more of
the genes that are responsible for directing the eyes and skin to
make melanin (pigment). As a result, little or no pigment is made,
and the child's skin, eyes and hair may be colorless.
In most types of albinism, a recessive trait, the child inherits
flawed genes for making melanin from both parents. Because the task
of making melanin is complex, there are many different types of
albinism, involving a number of different genes.
It's also possible to inherit one normal gene and one albinism gene.
In this case, the one normal gene provides enough information in its
cellular blueprint to make some pigment, and the child will have
normal skin and eye color. They "carry" one gene for albinism. About
one in 70 people are albinism carriers, with one flawed gene but no
symptoms; they have a 50% percent chance of passing the albinism
gene to their child. However, if both parents are carriers with one
flawed gene each, they have a 1 in 4 chance of passing on both
copies of the flawed gene to the child, who will have albinism. (There
is also a type of ocular albinism that is carried on the X
chromosome and occurs almost exclusively in males because they have
only one X chromosome and, therefore, no other gene for the trait to
override the flawed one.)
Symptoms of albinism can involve the skin, hair, and eyes. The skin,
because it contains little pigment, appears very light, as does the
hair.
Although people with albinism may experience a variety of eye
problems, one of the myths about albinism is that it causes people
to have pink or red eyes. In fact, people with albinism can have
irises varying from light gray or blue to brown. (The iris is the
colored portion of the eye that controls the size of the pupil, the
opening that lets light into the eye.) If people with albinism seem
to have reddish eyes, it's because light is being reflected from the
back of the eye (retina) in much the same way as happens when people
are photographed with an electronic flash.
People with albinism may have one or more of the following eye
problems:
They may be very far-sighted or near-sighted, and may have other
defects in the curvature of the lens of the eye (astigmatism) that
cause images to appear unfocused.
They may have a constant, involuntary movement of the eyeball called
nystagmus.
They may have problems in coordinating the eyes in fixing and
tracking objects (strabismus), which may lead to an appearance of
having "crossed eyes" at times. Strabismus may cause some problems
with depth perception, especially at close distances.
They may be very sensitive to light (photophobia) because their
irises allow "stray" light to enter their eyes. It's a common
misconception that people with albinism shouldn't go out on sunny
days, but wearing sunglasses can make it possible to go outside
quite comfortably.
In addition to the characteristically light skin and eye problems,
people with a rare form of albinism called Hermansky-Pudlak Syndrome
(HPS) also have a greater tendency to have bleeding disorders,
inflammation of the large bowel (colitis), lung (pulmonary) disease,
and kidney (renal) problems. |
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| ALBINISM RELATED ITEMS |
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