About Tay-Sachs Disease

Tay-Sachs is a hereditary disease, the result of a genetic defect which is passed from parents to children. When it occurs in children, it is a fatal and incurable disease of the nervous system and brain. Thus it is vitally important that persons at high risk for carrying Tay-Sachs undergo genetic testing and counseling for prevention purposes.

At higher risk for Tay-Sachs are people of central and eastern European Jewish communities, those in the Cajun population of Louisiana, and some French-Canadian communities in Quebec.

The genetic defect carried in Tay-Sachs causes a toxic build-up of a fatty material in the brain, called GM2 gangliosides. This is due to the body's inability to create enough of the enzyme hexosamidinase, which would normally function to break up the fat.

This disease normally presents in infancy or childhood, but in the rarer Adult Onset Tay-Sachs, the disorder is milder and in most cases, not fatal.

Symptoms

Tay-Sachs symptoms may not show for the first six months of infancy. However, as the disease progresses and nerve cells deteriorate, the child will become unable to swallow, suffer loss of hearing and vision, have difficulty breathing, and lose mental capacity. There is muscle wasting and paralysis. An infant with Tay-Sachs will usually die by four years of age.

In cases of the very rare Juvenile Onset Tay-Sachs disease, the disorder does not present symptoms until between the ages of two and ten. The individual will begin to show unsteady gait and spasticity. Problems with speech, cognition, breathing, and swallowing will occur. These patients rarely survive past the age of fifteen.

Late onset Tay-Sachs is even less common than the juvenile onset form, and has often been misdiagnosed as some other neurological disorder. These patients usually present with psychiatric or motor dysfunction, and possibly seizure activity. This form usually first shows symptoms in early adulthood in the individual's late teens, 20s or early 30s. It is rarely fatal.

Diagnosis

Tay-Sachs patients usually is determined with a physical examination following an interview for symptoms and family history. Many times, an eye examination will reveal a red spot at the back of the eye, which is a sign indicating Tay-Sachs disease. A blood test will be done on the child to test for the crucial enzyme, and usually on the biological parents as well, for genetic determination.

Treatment

For children with terminal Tay-Sachs, treatment consists of methods to keep the patient comfortable. To help in pain prevention, medications may be used. Physical therapy is provided to keep the joints and muscles from losing flexibility. Respiratory therapy is given to keep the lungs working and to prevent infection, which is common in Tay-Sachs patients. Nasogastric tubes or percutaneous esophago-gastrostomy (PEG) tubes are normally placed for feeding purposes. PEG tubes are inserted surgically and are a more long-term solution.

For patients with adult onset Tay-Sachs, many of the symptoms may be managed with medications as well as physical, speech and mental health therapies where necessary.

Gene therapy research is ongoing, and it is hoped that soon a cure or treatment to slow progression can be found for Tay-Sachs disease. Meanwhile, education and prevention in populations at higher risk to carry the disorder is crucial.

Sources:

Mayo Clinic

Signet/Mosby Medical Encyclopedia

National Institute of Health