"His
hair was white as snow, and his eyes like the rays of the sun".
This passage, from a religious text, cause some to speculate that
Noah might have inherited albinism. Albinism is a genetic disorder,
which means it passed from parents to future generations. People with
albinism have a defect in the gene that makes melanin. Melanin is
a pigment, which gives color to our hair, skin, and eyes. Because
albinism is an autosomal recessive gene, both parents must carry the
defective gene in order for a child to inherit this disease.
About 1 in 70 people have a gene for albinism, and 1 in 17,000 suffers
from the disease. Albinism affects all races of people. Most people
with albinism have very light skin and hair, and look only slightly
different from the rest of the family members. There are different
types of albinism; some can make melanin in the eyes, but not in the
hair or skin. Others have little or no ability to produce this pigment
at all. Ocular albinism involves the eyes, while the hair and skin
may look slightly lighter, which accounts for between 10 - 15 percent
of all cases. Oculocutaneous albinism is by far the more common form
affecting the eyes, hair and skin.
While
light-colored hair due to the lack of melanin has no medical consequences.
Melanin is important because it absorbs ultraviolet light from the
sun. In a person without albinism, exposure to the sun results in
tanning. People with albinism make little or no melanin, and as a
result, their skin sunburns due to sun exposure very easily. In tropical
areas, people with albinism who do not use sunscreen or wear opaque
clothes get skin cancers.
The eye also needs melanin to develop normally during development.
It is not completely understood why, but melanin is also important
to establish normal nerve connections between the eye and the brain.
Because the nerve connections are organized differently from normal,
which causes low vision and prevents the eye from working well together,
resulting in reduced depth perception. The colored area in the center
of the eye, the iris, does not produce enough melanin to keep extra
light from coming into the eye and hence causes sensitivity to the
sun. Usually people with albinism have an iris color of bluish gray
or light brown. It is a common myth that people with albinism have
red eyes.
Until recently, unless a couple had a child with albinism, there was
no way of knowing whether they were carriers of the gene for albinism.
With recent advances in genetics, doctors are now able to use a simple
blood test to detect and classify the more then 20 different types
of albinism. People with the type-II albinism have only slight pigmentation,
and usually slight visual problems. Those with type-I albinism have
no melanin production, and generally more trouble with their vision.
A similar test can identify the type I or II albinism, in an unborn
fetus, by aminiocentesis. Unfortunately, for couples that have not
had a child with albinism, because there are so many types of albinism,
the tests are not always conclusive.
Myths are associated with albinism in cultures throughout the world.
Popular, even today is the notion that people with albinism are retarded.
In fact, people with albinism develop normally, have normal intelligence,
and an average life span. One of the greatest risks for people with
albinism is isolation because of the dramatically different appearance,
especially in non-white races and communities. People with albinism,
especially children need to be included in social activities as much
as possible.
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