A Multi-system Disease
Ataxia-telangiectasia, or “A-T,” is a progressive, degenerative disease that affects a startling variety of body systems. The first signs of the disease usually appear early in childhood (the toddler stage), when children begin to walk. Though they usually start walking at a normal age, they wobble or sway when walking, standing still or sitting. In late pre-school and early school age, children with A-T develop difficulty moving the eyes in a natural manner from one place to the next, and they develop slurred or distorted speech, and swallowing problems.
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.
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 seemingly 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 immunoglobulins (IgG, IgA, IgM or IgG subclasses), 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 standard levels of therapeutic radiation or radiomimetic drugs (chemotherapy drugs that work in a way that is similar to radiation therapy) usually given to cancer patients.
Other Features of A-T
Other features of ataxia-telangiectasia that may affect some children are: 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, most individuals with A-T are very socially aware and socially skilled.
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 between 1 in 40,000 and 1 in 100,000 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.
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 early or mid-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.