Tay-Sachs disease is an incurable neurodegenerative disorder. Though very rare, certain couples may be at higher chance for having a baby with the condition.

Here’s what you should know about the disease, how to assess your risk factors and the treatments for giving babies with Tay-Sachs the best possible quality of life. 

What is Tay-Sachs disease?

Tay-Sachs disease is an inherited disorder that causes a progressive deterioration of the nerve cells in a baby's brain and spinal cord. In order for an infant to have this disease, both parents must be carriers of Tay-Sachs and each will have transmitted that gene to their child.

While a baby with Tay-Sachs might appear healthy at birth, the disease typically begins showing mental and physical symptoms between 3 and 6 months of age. 

What causes Tay-Sachs disease?

Tay-Sachs disease occurs when two parents, each of whom are carriers, both transmit the gene to their baby. A child who inherits two Tay-Sachs genes is born without the vital enzyme beta-hexosaminidase A (HEX-A), which is tasked with breaking down fatty waste substances found in brain cells.

Without the enzyme to help clear these fatty substances, they build up over time to toxic levels in the brain and spinal cord, as well as other parts of the body. Over time, this causes damage to the nervous system until it can no longer sustain life. 

Who is most at risk for Tay-Sachs disease?

The overall prevalence of Tay-Sachs disease in the general population is about 1 in 200,000 births with the genetic mutation that causes Tay-Sachs more common in certain ethnic groups. Jewish people of Eastern or Central European descent (Ashkenazi) have the highest risk, with approximately 1 in 30 being carriers of the mutation, affecting about one in 2,500 to 3,900 births.

Those of French Canadian descent or of the Cajun community of Louisiana have a higher risk than the general population, as do those of Irish and Pennsylvania Dutch descent.

Screenings for Tay-Sachs disease

An enzyme screening blood test can determine whether or not you or your partner are carriers of Tay-Sachs disease. These tests look for mutations in hexosaminidase A or Hex-A, the gene associated with Tay-Sachs. They’re about 95 percent accurate among the Ashkenazi Jewish population and 60 percent accurate among the general population. 

Remember that even if you have no family history of Tay-Sachs disease, several of your relatives as well as your parents could be carriers. This means Tay-Sachs can travel through a family tree hidden until it surfaces unexpectedly and tragically. If you or your partner can trace your lineage back to areas that are at increased risk for the Tay-Sachs gene, talk to your health care provider or a genetic counselor about getting tested, which can be done before you conceive or during pregnancy.

If you or your partner don’t have information about your family lineage but are concerned about Tay-Sachs or other potential genetic disorders, you can still ask your provider about carrier screening options. While Tay-Sachs carrier screenings are only routinely recommended on the basis of family history or ethnicity, both the American College of Obstetricians and Gynecologists (ACOG) and the American College of Medical Genetics and Genomics (ACMG) say that all couples should be offered the option to undergo carrier screening, if they choose, before trying to conceive.

If you're already pregnant, invasive tests like chorionic villus sampling (CVS) and amniocentesis can tell you if your baby has Tay-Sachs. Your provider can help you weigh the pros and cons of these tests to determine if one is right for you. 

What’s the probability that my child will have Tay-Sachs disease?

Your chances of having a baby with Tay-Sachs disease are very rare, but it’s important to get tested if both you and your partner have ancestries that are linked to an increased risk. In situations where one parent is a carrier of the Tay-Sachs gene, there is no chance that the child will have Tay-Sachs disease. But with each pregnancy, there is a 50 percent (2 in 4) chance of having a baby who is a carrier of Tay-Sachs disease.

Even in situations where both parents are carriers, there is still only a 25 percent (1 in 4) chance with each pregnancy of having a baby who is born with Tay-Sachs disease. If both parents are carriers, their chances of having a child who merely carries the Tay-Sachs gene is 50 percent (2 in 4).

Symptoms of Tay-Sachs disease in babies

A baby born with Tay-Sachs disease typically experiences normal development until 3 to 6 months of age, when signs of the disorder gradually begin to appear. These can include:

  • Loss of or failure to develop motor skills like rolling over, sitting up or crawling 
  • Progressive vision and hearing loss
  • Exaggerated startle reaction to loud noises
  • Seizures
  • Cherry-red spot that forms in the back of the eyes
  • Muscle weakness and movement problems

Treatment for Tay-Sachs disease

There is no known cure for Tay-Sachs disease, and tragically, most children with the disorder don’t live beyond age 4. However, children can experience a better quality of life with treatments aimed at relieving and managing symptoms. These can include:

  • Anti-seizure medications
  • Respiratory care to reduce the risk of lung infections
  • Assistive feeding devices to help children get adequate nutrition and hydration
  • Physical therapy to maintain flexibility and range of motion

Researchers are working to develop treatments that could potentially cure Tay-Sachs or slow its progression. Options like enzyme replacement therapy (ERT), gene replacement therapy, chaperone therapy and substrate reduction therapy are currently under investigation and could help children with Tay-Sachs lead longer, healthier lives in the future. The therapies haven’t yet been shown to improve symptoms, however, the National Organization for Rare Disorders (NORD) notes that scientists are hoping to soon conduct clinical trials using gene therapy.

For now, there’s no known way to prevent the genetic mutation that causes Tay-Sachs. But there are options available to couples who may learn that they are both genetic carriers of Tay-Sachs.

Seeking the help of a genetic counselor is a good place to start. Together, you can learn about your chances for having a child with Tay-Sachs, or, if you’re currently pregnant, coordinate with a medical specialist to determine the best plan of action for your family.