What Is Albinism?
Albinism Causes (AL-bi-niz-im) is a group of disorders that occur when a person
inherits various genes* that are defective in their ability to make the pigment
melanin (MEL-a-nin). Melanin is the main substance that determines a
person’s skin, hair, and eye color. In the United States, albinism affects
approximately one in 17,000 people, although certain types of albinism
are more prevalent among specific groups of people. In some parts of
Africa, for instance, about one in 1,000 people experience the condition.
The outward signs of albinism vary depending on the amount of pigment
a person has, and many people with albinism have skin much lighter
than that of their family members. Caucasians with albinism may have white
to light-blond hair, pinkish-white skin, and blue eyes, while people who are
black may have yellowish hair, skin with a cream-colored tint, and hazel or
green eyes. In some people with albinism, the eyes look pink because they
contain no pigment to mask the red of the blood vessels in the retina*.
Albinism always affects vision to some degree. The genes responsible
for albinism cause abnormal development of the nerve connections
between the eyes and the brain. The retina and the iris (the colored portion
of the eye) are also affected by albinism.
What Albinism Causes?
Albinism Causes refers to a group of inherited disorders that are often divided into
two major categories: oculocutaneous albinism, or OCA, which involves
eye, hair, and skin color; and ocular albinism that mainly affects the eyes.
Some of these disorders and their causes are:
■ OCA type 1: This form of albinism, which is characterized by almost
no pigmentation, is caused by a defect in a gene for an enzyme* called tyrosinase that normally is involved in producing melanin. OCA
type 1 is more common among Caucasians than among people of
African descent. Overall, it affects about one in 40,000 people.
■ OCA type 2: This form of albinism, which is characterized by some
pigmentation, is caused by a defect in what is called the “P” gene.
It affects about one in 15,000 people overall but is especially prevalent
among African and African-American populations, in which it
affects approximately one in 10,000 individuals.
■ Hermansky-Pudlak syndrome (HPS): This form of albinism, which
is characterized by easy bruising and bleeding and by a susceptibility
to lung and bowel disease, is caused by a different defective gene.
Skin, hair, and eye color vary from person to person with HPS.
Although this form of albinism is rare overall, it is much more
common in Puerto Rico, where it occurs in about one in 1,800.
■ Ocular (eye) albinism: This form of albinism, which affects mainly
the eyes, includes several disorders that are also gene-related. People
with ocular albinism often have no loss of pigmentation in the hair
Most people with albinism are born to parents without the condition,
but both parents must carry a copy of the defective gene, and both must
pass on that copy to their child. Albinism is a recessive trait, meaning that
if a person inherits even one good copy of the gene, he or she will not
have the condition. Parents who both carry the trait have a 25 percent
chance that each of their newborn children—either boy or girl—will have
albinism. Ocular albinism is the exception because most of these cases are
caused by a sex-linked genetic defect, which means that the defective gene
is carried by the X chromosome*, which is one of two chromosomes that
determine a person’s sex. Sex-linked diseases occur most often in males.
Living with Albinism
Vision and skin care are major considerations for people with albinism. The
lack of pigment makes eyes and skin very sensitive to sunlight and the skin
prone to sunburn. The latter, a feature of people with oculocutaneous albinism,
can lead to premature aging of the skin and skin cancer. The use of
sunscreen, hats, and/or protective clothing can help prevent overexposure
to the sun. Similarly, people with oculocutaneous and with ocular albinism
should use sunglasses to shade their eyes and should take care to avoid direct
and bright indoor lights, as well as glare from shiny surfaces both indoors and
outdoors. Some people with albinism find that their vision problems can be
corrected with glasses, but others may require surgery. While many people
with albinism can see well enough to drive a car, many others are legally
blind. All people with albinism need consistent and continuing eye care.
While people with most forms of albinism have a normal life expectancy,
they may face social and emotional hurdles as they learn to live
with being different. Support from family and friends is especially important
to helping a child with albinism build self esteem.
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