Tay-Sachs disease (TSD) is a genetic disorder. It is when a fatty substance builds up in the brain. This causes progressive destruction of the brain. There are three forms:

  • Infantile-onset—usually fatal before 5 years of age
  • Juvenile-onset—usually fatal in late childhood or adolescence
  • Adult-onset—may survive up to 60 years of age


TSD is caused by the absence of an enzyme. This enzyme is needed to break down a fatty substance called ganglioside (GM2). GM2 builds up without it. The buildup in the brain causes damage.

It happens when both parents pass on the faulty genes. A person can have just one copy of the faulty gene. In this case, there are no symptoms. The person is called a carrier.

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Risk Factors

Having parents who are carriers of the TSD gene is the most common risk factor.

TSD is found in specific ethnic groups:

  • Those of Eastern European (Ashkenazi) Jewish descent
  • French Canadians living in eastern Quebec and New England
  • Some Cajun populations in Louisiana
  • Non-Amish Pennsylvania Dutch


Babies with TSD may seem to develop normally until about four to five months of age when symptoms begin to start. Babies may have:

  • Floppy body position
  • Shrill cry
  • Decreased eye contact
  • Increased startle reaction
  • Loss of motor skills
  • Enlarged head
  • Vision loss or blindness
  • Deafness
  • Problems swallowing
  • Muscular difficulties such as spastic muscles, weakness, or paralysis
  • Learning problems
  • Seizures

In some cases, the symptoms do not begin until age 2-5 years old. The condition progresses slowly. Symptoms may include:

  • Loss of the ability to speak
  • Developmental delay and learning problems
  • Loss of bowel control
  • Sleep problems
  • Movement disorder, such as difficulty walking and muscle weakness
  • Tremor
  • Slurred speech
  • Mental health problems
  • Loss of vision
  • Spasticity and seizures


You will be asked about your child's symptoms and health history. A physical exam will be done.

Blood tests will be done.

Imaging tests may be done, such as:


TSD can’t be cured. Treatment is aimed at managing symptoms.


TSD can’t be prevented. If you are a carrier of the gene that causes TSD, you can talk to a genetic counselor before deciding to have children.


Genetic Alliance

National Tay-Sachs and Allied Diseases Association, Inc.


About Kids Health—The Hospital for Sick Children

Caring for Kids—The Canadian Paediatric Society


Fernandes Filho JA, Shapiro BE. Tay-Sachs disease. Arch Neurol. 2004;61(9):1466-1468.

Tay-Sachs disease. EBSCO DynaMed Plus website. Available at: Updated November 14, 2017. Accessed July 6, 2018.

NINDS Tay-Sachs disease information page. National Institute of Neurological Disorders and Stroke website. Available at: Accessed July 6, 2018.

Last reviewed May 2018 by Kari Kassir, MD  Last Updated: 7/6/2018