Tay-Sachs is a disease of the central nervous system. It’s a neurodegenerative disorder that most commonly affects infants. In infants, it’s a progressive disease that is always fatal.
Although rare, Tay-Sachs can also occur in teens and adults, causing less severe symptoms.
Symptoms of infantile Tay-Sachs
Most infants with Tay-Sachs disease have nerve damage starting in utero (before birth), with symptoms usually appearing from age 3 to 6 months. Progression is rapid, and the child may live to age 4 or 5.
Symptoms of Tay-Sachs in infants include:
- progressive blindness
- decreased muscle strength
- increased startle response
- paralysis or loss of muscle function
- muscular stiffness (spasticity)
- delayed mental and social development
- slow growth
- 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 911 immediately.
Symptoms of other forms of Tay-Sachs
There are also juvenile and adult forms of the disease, which occur less frequently.
People with the juvenile form typically display symptoms between the ages of 2 and 5 and may live to age 15. Symptoms may include muscle weakness, seizures, and recurring respiratory infections.
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 these symptoms:
- muscle weakness
- slurred speech
- unsteady gait
- memory problems
The severity of symptoms and life expectancy varies.
A defective gene on chromosome 15 causes Tay-Sachs disease. This defective gene results in the body not making a protein called hexosaminidase A (HEX-A).
Without this protein, a molecule called GM2 ganglioside builds up in nerve cells in the brain, destroying these cells.
Tay-Sachs disease is hereditary, which means it’s passed down through families. You have to receive two copies of the defective gene — one from each parent — to inherit the disease.
If only one parent passes down the defective gene, the child becomes a carrier. They won’t inherit the disease, but they may pass it to their own children.
The disease 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 are a Tay-Sachs carrier.
There’s no way to prevent the disease, but you can undergo genetic testing to see if you’re a carrier or if the fetus has the disease.
If you or your spouse is a carrier, genetic testing can help you decide whether or not to have children.
Prenatal tests, such as chorionic villus sampling (CVS) and amniocentesis, can diagnose Tay-Sachs disease. Genetic testing is generally done when one or both members of a couple are carriers 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 mother’s abdomen.
If a child is displaying symptoms of Tay-Sachs disease, a doctor can perform a physical examination 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 the quality of life for the patient and family. This is also known as palliative care.
Palliative care may include:
- medication for pain
- anti-epileptic medication to control seizures
- physical therapy
- nutritional support
- respiratory treatments to reduce mucus buildup in the lungs
Emotional support for the family is also important. Seeking out support groups can help you cope.
Taking care of a sick child is emotionally challenging and 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 GM2 ganglioside buildup, which 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.
- 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 under genetic testing to see if they’re carriers of the disease.
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.