Tay-Sachs disease is a genetic disorder that leads to the premature death of young children. There is currently no treatment or cure.
What is Tay-Sachs disease?
Tay-Sachs disease is caused by a deficiency in an ezyme that is needed for your brain to function properly. That deficiency is caused by a problem with the HEXA gene.
The genetic disorder is more common in Ashkenazi Jews, a group of people whose heritage is from central and eastern Europe. It is also fairly common in people from French-Canadian communities in Quebec, Cajun communities in Louisiana and Amish communities in Pennsylvania.
Tay-Sachs disease is an autosomal recessive disorder, which means that a child must inherit faulty HEXA genes from both parents to have Tay-Sachs disease. If both parents are carriers of faulty HEXA genes there is a:
- 1 in 4 chance that a child will be healthy and not a carrier
- 1 in 4 chance that a child will inherit Tay-Sachs disease
- 1 in 4 chance that a child will be healthy, but a carrier.
If one parent is a carrier, there is 1 in 2 chance of a child also becoming a carrier.
Types of Tay-Sachs disease
There are 2 main types of Tay-Sachs disease - the infantile form, which is far more common, and the late-onset form.
Signs and symptoms of Tay-Sachs disease
Babies with infantile Tay-Sachs disease appear healthy at birth. But by the time they are 6 months old, their development is slowing. They gradually lose power and movement in their limbs, and gradually lose their vision. Over time the children regress in other ways, losing the power of speech and many other functions. Most children with infantile Tay-Sachs disease die before getting to school age.
For those with late-onset Tay-Sachs disease, things move more slowly. The early signs are usually things like clumsiness and muscle weakness.
Screening for Tay-Sachs disease
In Australia there are community genetics screening programs for people of Ashkenazi Jewish heritage, who have a one in 25 likelihood of being carrying a faulty HEXA gene. The screening is not perfect and will pick up only the most common problems with the HEXA gene. If your heritage puts you at risk of being a carrier of Tay-Sachs disease, talk to your doctor.
Diagnosis of Tay-Sachs disease
Tay-Sachs disease may be diagnosed following a clinical examination or by performing biochemical and/or genetic testing on a blood sample.
Treatment of Tay-Sachs disease
There is currently no cure or effective treatment for Tay-Sachs disease, though some treatments may ease symptoms.
Where to go for help?
It is best to talk to either your doctor or a genetic counsellor. To find a genetic counsellor, go to the Australian Society of Genetic Counsellors.
Last reviewed: September 2016