Tay-Sachs Disease (Infantile Form)

Tay-Sachs disease is a deadly genetic disease of the central nervous system. (Read about "Genetics") According to the March of Dimes (MOD), the most common form of Tay-Sachs affects babies. The infant may appear to develop normally for the first few months of life, but development slows and symptoms appear. Babies with Tay-Sachs are lacking an enzyme called hexosaminidase A or hex A. This enzyme or protein, according to MOD, is necessary for breaking down certain fatty substances in brain and nerve cells. As these substances build up, they slowly eat away at brain and nerve cells until the central nervous system ceases to work. (Read about "The Brain" "Nervous System") Death usually occurs by age 5. Classic Tay-Sachs symptoms usually appear at 4 to 6 months of age. (Read about "Child Development") According to MOD, a healthy child may exhibit the following:

• stops smiling
• stops crawling or turning over
• can't grasp objects or reach out
• becomes blind
• becomes paralyzed
• is unaware of surroundings

MOD says some people are more at risk for this disease than others. The high-risk groups include:

• descendants of Central and Eastern European Jews. (about 1 in 30 American Jews is a carrier)
• some non-Jewish individuals of French-Canadian ancestry
• members of the Louisiana Cajun population

According to the National Institute of Neurological Disorders and Stroke (NINDS), there is a much rarer form of the disease. It occurs in patients in their twenties and thirties. NINDS says an unsteadiness of gait and progressive neurological deterioration mark the symptoms of this form of Tay-Sachs.

Testing

There is a simple blood test that can determine whether a person is a carrier of the disease. (Read about "Laboratory Testing") The test, according to NINDS, measures hexosaminidase A activity. Both parents must be carriers to have a child affected by Tay-Sachs. If that is the case, there is a 25 percent chance with each pregnancy that the child will have the disease. By testing before conception, a couple will know if they are both carriers. If they are, then they can follow up with appropriate testing, such as CVS and amniocentesis during the pregnancy. (Read about "Pregnancy Testing")

Treatment

Currently there is no treatment for Tay-Sachs disease. However, according to MOD, researchers are looking for answers. They have helped pinpoint the various mutations in the hex A gene that are responsible for hex A deficiency. This may help lead to improved diagnosis and screening for all forms of Tay-Sachs. Meanwhile, gene therapy is already being tested in patients with several other genetic diseases. This revolutionary treatment may help to cure or alleviate symptoms of some hereditary disorders. MOD says this approach may someday help children with Tay-Sachs disease.

Related Information:

    Birth Defects