A Multi-system Disease...
Ataxia-telangiectasia, or "A-T," is a progressive, degenerative
disease that affects a startling variety of body systems. Children with A-T
appear normal at birth, and the first signs of the disease usually appear during
the second year of life. These first signs are usually a "wobbly" lack of
balance and slurred speech caused by "ataxia," which means a lack of muscle
control.
Ataxia...
The onset of this ataxia marks the beginning of progressive
degeneration of a part of the brain, known as the cerebellum, that gradually
leads to a general lack of muscle control, and eventually confines the patient
to a wheelchair. Because of the worsening ataxia, children with A-T lose their
ability to write, and speech also becomes slowed and slurred. Even reading
eventually becomes impossible as eye movements become difficult to control.
Telangiectasia...
Soon after the onset of the ataxia, the A-T patient usually shows
another clinical hallmark of A-T: "telangiectasia," or tiny red "spider" veins
which appear in the corners of the eyes or on the surface of the ears and cheeks
exposed to sunlight. Although these telangiectasia are harmless, their unique
appearance together with ataxia is what led to naming this disease
"ataxia-telangiectasia".
Immune System Problems...
For most (about 70 percent) of children with A-T there is another
clinical hallmark: immunodeficiency that usually brings
recurrent respiratory infections. In many patients, these infections can become
life threatening. Because of deficient levels of IgA and IgE immunoglobulins,
the natural infection fighting agents in the blood, children with A-T are highly
susceptible to lung infections that do not respond to typical antibiotic
treatments. For these A-T patients, the combination of a weakened immune system
and the progressive ataxia can ultimately lead to pneumonia as a common cause of
death.
Predisposition to Cancer...
Children with A-T tend to develop malignancies of the blood
system almost 1,000 times more frequently than the general population. Lymphoma
and leukemia are particularly common types of cancer, although the frequencies
of most cancers are elevated. Ironically, another facet of the disease is an
extreme sensitivity to radiation, which means that A-T patients cannot tolerate
the therapeutic radiation usually given to cancer patients.
Other Features of A-T...
Other features of ataxia-telangiectasia that may affect some
children are: mild diabetes mellitus, premature graying of the hair, difficulty
swallowing causing choking and/or drooling and slowed growth. Even though A-T is
a multi-system disorder, the children afflicted have and maintain normal or even
above-normal intelligence. Their dispositions seem to remain equable and help
them to maintain a healthy outlook on life despite the progression of their
disabilities.
How Frequent is A-T?
Ataxia-telangiectasia respects no racial, economic, geographic or
education barriers. Both males and females are equally affected. Epidemiologists
estimate the frequency of A-T as 1 in 40,000 births. But it is believed that
many children with A-T, particularly those who die at a young age, are never
properly diagnosed. Therefore, this disease may actually be much more common.
The Prognosis...
A-T is presently incurable and unrelenting. If they are lucky
enough not to develop cancer, most A-T children are dependent on wheelchairs by
the age of ten, not because their muscles are too weak, but because they cannot
control them. Later, A-T patients usually die from respiratory failure or cancer
by their teens or early twenties. A few A-T patients live into their forties,
but they are extremely rare.
What treatments are available?
There is no cure for A-T, and there is currently no way to slow
the progression of the disease. At this time, treatments are directed only
toward partially alleviating some symptoms as they appear. Because A-T is a
rare, "orphan" disease, very little research data is available on pharmaceutical
therapies that may aid these children. Physical, occupational and speech therapy
are used to help maintain flexibility, gamma-globulin injections help supplement
the immune systems of A-T patients, and high-dose vitamin regimes are being
undertaken with some moderate results.
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