How Do I Know If My Baby Has Tay-Sachs Disease?

The first signs of Tay-Sachs disease often appear when babies are between 3 and 6 months old. If you've noticed that your baby's muscles seem weak or your child has stopped sitting up or rolling over, you might have reason to look into it further.

Tay-Sachs is very rare. There's a good chance something else is behind your baby's symptoms.

A visit to your doctor for an exam and tests will help you find out for sure. Once you have a diagnosis, you can make important decisions and get your baby the right kind of medical care.

Who Is More Likely to Get It?

Tay-Sachs is an inherited disease caused by a faulty gene. This particular gene tells the body how to make an important enzyme called hexosaminidase A (Hex-A).

Enzymes are proteins that speed up reactions in the body. The Hex-A enzyme breaks down fatty waste products in the brain. Without it, the fat builds up and damages the baby's brain and nervous system.

A baby has to inherit the faulty gene from each parent to get Tay-Sachs disease. An infant who inherits two copies of the mutated gene can't make any of the Hex-A enzyme and is certain to develop Tay-Sachs disease. If both parents carry the Tay-Sachs gene, each of their children has a 25% chance of having the disease.

People whose families are of European Jewish descent (“Ashkenazi” Jews) are most likely to carry the Tay-Sachs gene. About 1 out of every 27 Jewish people in the United States has this gene. You're also more likely to carry this gene if your family comes from one of these places:

  • The French part of Canada
  • The Cajun community of Louisiana
  • Ireland


What Are the Signs of Tay-Sachs?

Babies with Tay-Sachs look and act just like other babies until they're about 3 to 6 months old. Then their development starts to go backward.

They stop being able to crawl, roll over, sit, or reach for things like they used to do. They may not smile or respond when you talk to them. Over time, they lose the ability to see, hear, and move.

Other signs include:

  • An extreme response to sudden sounds
  • Irritability
  • Low muscle tone
  • Muscle spasms that make movements stiff
  • Red spots in the back of the eyes that can be discovered during an exam
  • Seizures

Call your doctor if your baby loses any of the skills they once had or if you notice any of these symptoms.


Your doctor can do a blood test before you get pregnant to find out whether you and your partner carry the gene that causes Tay-Sachs.

If you both have the gene, you might want to see a genetic counselor. Then you can decide whether to start a family.

Two tests that you get during your pregnancy can show whether your baby has Tay-Sachs:

Chorionic villus sampling (CVS): This test is done between your 10th and 12th weeks of pregnancy. Your doctor puts a thin needle into your belly or places a tube through your vagina into your cervix.

Then they remove a small piece of tissue from the placenta, the organ that gives your baby nutrients and oxygen. The tissue goes to a lab to be tested.

Amniocentesis: This test is done between your 15th and 18th weeks of pregnancy. Your doctor uses a thin needle to remove a sample of amniotic fluid. This is the fluid that surrounds your baby in the womb. The fluid goes to a lab. It's tested to see whether your baby has Tay-Sachs.

If you suspect your baby has the disease, see your doctor. They will ask about their symptoms and your family history.

A blood test can show if your baby has the Hex-A enzyme. Babies who are missing this enzyme have Tay-Sachs. The doctor can also do an eye exam to look for a red spot in your baby's macula, a part of the retina in the back of the eye.


After the Diagnosis

Once you have a diagnosis, you and your doctor can talk about your options. Though there is no cure, treatments can manage your baby's symptoms and keep them comfortable.

Doctors are researching new ways to treat this disease. These are tested in clinical trials. Ask your doctor whether a trial might be right for your child.

WebMD Medical Reference Reviewed by Dan Brennan, MD on October 14, 2020



Cleveland Clinic: "Tay-Sachs Disease."

March of Dimes: "Amniocentesis," "Chorionic villus sampling."

National Human Genome Research Institute: "Learning About Tay-Sachs Disease."

National Organization for Rare Disorders: "Tay Sachs Disease."

National Tay-Sachs & Allied Diseases Association of Delaware Valley: "Tay-Sachs Disease."

Nemours Foundation: "Tay-Sachs Disease."

U.S. National Library of Medicine: "Tay-Sachs Disease."

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