Tay-Sachs is a rare disease of the central nervous system that most commonly affects infants. In infants and young children, it’s a progressive disease that is always fatal.
Tay-Sachs can also occur in teens and adults, causing less severe symptoms.
It’s caused by problems with an enzyme known as hexosaminidase A (Hex-A) that’s important for your brain. People with Tay-Sachs don’t have enough of this enzyme. As a result, a fatty substance (lipid) builds up and causes damage to the brain and spinal cord.
Tay-Sachs is inherited, meaning it is passed down through families. There’s no known cure, but testing can tell you whether you’re at risk for passing Tay-Sachs to your children.
Infantile Tay-Sachs is the most common form. There are also juvenile and adult forms of the disease, which occur less frequently.
The age of onset differs based on the amount of Hex-A enzyme activity. The less enzyme activity someone has, the earlier their symptoms will appear. With lower enzyme activity, symptoms are also more severe.
Symptoms of infantile Tay-Sachs
Most infants with Tay-Sachs disease appear healthy at birth and for the first few months of life, with symptoms usually appearing from age 3 to 6 months. Progression is rapid, and a child with infantile Tay-Sachs may live to age 4 or 5.
Symptoms of infantile Tay-Sachs include:
- muscle weakness
- muscle twitching
- increased startle response
- declining motor skills
- slow growth
- hearing loss
- vision loss
- difficulty swallowing
- intellectual disability
- red spot on the macula (an oval-shaped area near the center of the retina in the eye)
If your child has a seizure or has trouble breathing, go to the emergency room or call your local emergency services immediately.
Symptoms of juvenile Tay-Sachs
People with the juvenile form typically display symptoms between ages 2 and 5. Symptoms slowly increase over time. Children with this form may live to about age 15.
Symptoms can include:
- uncoordinated movement, known as ataxia
- muscle weakness
- mood and cognitive symptoms
- difficulty with speech
- vision loss
- decreased responsiveness
Symptoms of adult Tay-Sachs
Adult Tay-Sachs, sometimes known as chronic or late onset Tay-Sachs, is the mildest form. Symptoms appear during adolescence or adulthood. People with the adult form of Tay-Sachs disease usually have symptoms such as:
The severity of symptoms and life expectancy varies. Medications and other supports, such as physical therapy and occupational therapy, can help make symptoms more manageable.
Tay-Sachs disease is hereditary, which means it’s passed down through families. A child has to receive two copies of the gene that causes Tay-Sachs — one from each biological parent — to inherit the disease.
People with two copies of the problem gene have trouble producing an enzyme called hexosaminidase A (Hex-A).
Without this enzyme, a lipid called GM2 ganglioside builds up in nerve cells in the brain, destroying these cells.
If only one parent passes down the affected gene, the child becomes a carrier. They won’t develop the disease, but they may pass it to their own children.
The gene that causes Tay-Sachs is most common among Ashkenazi Jews, whose families descend from Jewish communities in Central or Eastern Europe. According to the Center for Jewish Genetics, approximately 1 in 30 people in the Ashkenazi Jewish population is a Tay-Sachs carrier.
You’re also more likely to be a carrier if someone in your family had Tay-Sachs. This is true for people of all ethnicities and racial groups.
There’s no way to prevent the disease, but you can undergo genetic counselling and testing to see if you’re a carrier.
If you or your partner is a carrier, genetic testing can help you decide whether or not to have biological children.
Prenatal tests, such as chorionic villus sampling (CVS) and amniocentesis, can diagnose Tay-Sachs disease. Prenatal testing is available if you or your partner is suspected or known to be a carrier of the disease.
CVS is performed between 10 and 13 weeks of pregnancy and involves taking a sample of cells from the placenta via the vagina or abdomen.
Amniocentesis is done between 15 and 20 weeks of pregnancy. It involves extracting a sample of the fluid surrounding the fetus using a needle through the pregnant person’s abdomen.
If a child is displaying symptoms of Tay-Sachs disease, a doctor can perform a physical exam and collect a family history.
Enzyme analysis can be done using the child’s blood or tissue samples, and an eye exam may reveal a red spot on their macula (a small area near the center of the retina of their eye).
At present, there’s no cure for Tay-Sachs disease. Typically, treatment is supportive, focused on reducing symptoms and improving quality of life. This is also known as palliative care.
Treatments may include:
- medication for pain
- anti-epileptic medication to control seizures
- physical therapy
- nutritional support
- respiratory treatment
Emotional support for the family is also important. Seeking out support groups can help you cope.
It’s normal to experience a range of emotions when caring for a child with a serious disease. Talking with other families managing the same disease can be comforting.
Research is ongoing for more effective treatments for Tay-Sachs disease. Several options have shown some benefits in animals, but have had limited results in people. Potential treatments include:
- Enzyme replacement therapy. Since Tay-Sachs is caused by the lack of the Hex-A enzyme, this treatment seeks to replace the enzyme. So far, several complications have kept this from being effective for Tay-Sachs.
- Enzyme-enhancing therapy. This therapy uses molecules to stabilize enzymes and increase their activity. More research is needed on this treatment.
- Substrate reduction therapy. Instead of trying to increase the Hex-A enzyme, this uses small molecules to reduce the lipid buildup that damages nerve cells in people with Tay-Sachs.
- Gene therapy. Bringing new genetic information to cells may correct the enzyme defect that results in Tay-Sachs. The Food and Drug Administration (FDA) recently approved clinical trials to study the safety and effectiveness of gene therapy. It’s not yet known whether the new treatment will be effective and safe over time.
- Cell transplantation. This therapy uses bone marrow transplants to provide the missing enzyme. Studies have found benefits for animals, but more research is needed in humans.
Because Tay-Sachs is inherited, there is no way to prevent it except through screening. Before starting a family, both parents can undertake genetic testing to see if they’re carriers of the disease. This is most important for people at elevated risk, such as Ashkenazi Jews or people with a family history of Tay-Sachs.
Screening for carriers of Tay-Sachs started in the 1970s and has reduced the number of Ashkenazi Jews born with Tay-Sachs in the United States and Canada by over
Speak with a genetic counselor if you’re thinking about starting a family, and you or your partner believe you might be carriers of Tay-Sachs disease.
Is Tay-Sachs disease inherited?
Yes. Tay-Sachs disease is passed down from parents to children.
If a child receives two copies of the gene that causes Tay-Sachs — one from each parent — they will develop the disease. If a child receives one copy of the gene that causes Tay-Sachs, they will be a carrier. Being a carrier means that you can pass the gene to your own children.
Genetic testing can tell you if you are a carrier of the disease.
How long can you live with Tay-Sachs disease?
It depends. There are three forms of Tay-Sachs, and each one affects lifespan differently.
Infantile Tay-Sachs is the most common and most severe form. Unfortunately, infants diagnosed with Tay-Sachs have an average life expectancy of only 4 to 5 years.
Juvenile Tay-Sachs is usually diagnosed between ages 2 to 5. Sadly, children with Juvenile Tay-Sachs do not tend to survive into adulthood. The usual life expectancy is around age 15.
Adult Tay-Sachs has a wider range of life expectancies. It’s diagnosed in teens and adults. Adult Tay-Sachs can shorten lifespan for some people but not others.
How does Tay-Sachs disease affect everyday life?
In infants and children, Tay-Sachs disease affects a range of functions. A child may have trouble moving, seeing, and hearing, and symptoms will get worse over time. Treatment is focused on managing symptoms and living more comfortably.
Outcomes for people with adult Tay-Sachs are more variable. Many adults will need help with tasks of daily living, according to a
Why is there no cure for Tay-Sachs disease?
Researchers are working on treatments to slow or stop Tay-Sachs disease, but no cure or effective therapy has yet been found. Tay-Sachs is treated with medications and supports to manage symptoms and improve quality of life.
Potential new treatments could include gene therapy, bone marrow transplant, or therapies to target the enzymes or lipids involved in Tay-Sachs.
If you’re interested, you can ask your doctor about participating in clinical trials.