Tay-Sachs disease

  • Definition
    • Tay-Sachs disease is a life-threatening disease of the nervous system passed down through families.

  • Causes
    • Tay-Sachs disease occurs when the body lacks hexosaminidase A. This is a protein that helps break down a group of chemicals 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. They will not be sick, but may pass the disease to their own children.

      Anyone can be a carrier of Tay-Sachs. But, the disease is most common among the Ashkenazi Jewish population. 1 in every 27 members of the population carries the Tay-Sachs gene.

      Tay-Sachs is divided 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
  • Exams and Tests
    • The health care provider will examine the baby and ask questions about your family history. Tests that may be done are:

      • Enzyme exam of blood or body tissue for hexosaminidase levels
      • Eye exam (reveals a cherry-red spot in the macula)
  • Treatment
    • There is no treatment for Tay-Sachs disease itself, only ways to make the person more comfortable.

  • Support Groups
  • Outlook (Prognosis)
    • Children with this disease have symptoms that get worse over time. They usually die by age 4 or 5.

  • Possible Complications
    • 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
    • Go to the emergency room or call the local emergency number (such as 911) if:

      • Your child has a seizure of unknown cause
      • The seizure is different from previous seizures
      • The child has difficulty breathing
      • The seizure lasts longer than 2 to 3 minutes

      Call for an appointment with your health care provider if your child experiences a seizure lasting less than 2 to 3 minutes or has other noticeable behavioral changes.

  • Prevention
    • 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
    • Kwon JM. Neurodegenerative disorders of childhood. In: Kliegman RM, Stanton BF, St. Geme J III, Schor N, Behrman RE, eds. Nelson Textbook of Pediatrics. 19th ed. Philadelphia, PA: Elsevier Saunders; 2011:chap 592.