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Definition Return to top
Tay-Sachs disease is a deadly disease of the nervous system passed down through families.
Causes Return to top
Tay-Sachs disease occurs when the body lacks hexosaminidase A, a protein that helps break down a chemical found in nerve tissue called gangliosides. Without this protein, gangliosides, particularly ganglioside GM2, build up in cells, especially nerve cells in the brain.
Tay-Sachs disease is caused by a defective gene on chromosome 15. When both parents carry the defective Tay-Sachs gene, a child has a 25% chance of developing the disease. The child must receive two copies of the defective gene -- one from each parent -- in order to become sick. If only one parent passes the defective gene to the child, the child is called a carrier. He or she won't be sick, but will have the potential to pass the disease to his or her own children.
Anyone can be a carrier of Tay-Sachs, but the disease is most common among the Ashkenazi Jewish population. About 1 in every 27 members of the Ashkenazi Jewish population carries the Tay-Sachs gene.
Tay-Sachs has been classified into infantile, juvenile, and adult forms, depending on the symptoms and when they first appear. Most people with Tay-Sachs have the infantile form. In this form, the nerve damage usually begins while the baby is still in the womb. Symptoms usually appear when the child is 3 to 6 months old. The disease tends to get worse very quickly, and the child usually dies by age 4 or 5.
Late-onset Tay-Sachs disease, which affects adults, is very rare.
Symptoms Return to top
Exams and Tests Return to top
If Tay-Sachs disease is suspected, the doctor will perform aphysical examination and take a family history. Additional tests may include:
Treatment Return to top
There is no treatment for Tay-Sachs disease itself, only ways to make the patient more comfortable.
Support Groups Return to top
The stress of illness may be eased by joining support groups whose members share common experiences and problems. See Tay-Sachs - support group.
Outlook (Prognosis) Return to top
Children with this disease have symptoms that get worse over time. They usually die by age 4 or 5.
Possible Complications Return to top
Symptoms appear during the first 3 to 10 months of life and progress to spasticity, seizures, and loss of all voluntary movements.
When to Contact a Medical Professional Return to top
Go to the emergency room or call the local emergency number (such as 911) if your child has a seizure of unknown cause, if the seizure is different from previous seizures, if the child has difficulty breathing, or if the seizure lasts longer than 2 - 3 minutes.
Call for an appointment with your health care provider if your child experiences a seizure lasting less than 2 - 3 minutes or has other noticeable behavioral changes.
Prevention Return to top
There is no known way to prevent this disorder. Genetic testing can detect if you are a carrier of the gene for this disorder. If you or your partner are from an at-risk population, it is recommended that you undergo testing before starting a family. Testing the amniotic fluid can diagnose Tay-Sachs disease in the womb.
References Return to top
Johnston MV, Neurodegenerative Disorders of Childhood. In: Kliegman RM, Behrman RE, Jenson HB, Stanton BF, eds. Nelson Textbook of Pediatrics. 18th Ed. Philadelphia, Pa: Saunders Elsevier; 2007: chap 599.Update Date: 10/21/2008 Updated by: Luc Jasmin, MD, PhD, Departments of Anatomy and Neurological Surgery, University of California, San Francisco, CA. Review provided by VeriMed Healthcare Network. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.