Tay-Sachs Disease

Genetic Testing for Tay-Sachs

When there is a family history of Tay-Sachs disease or individuals are from high-risk populations, couples who are planning children are advised to get genetic counseling.

A blood test measures levels of the hexosaminidase A (hex A) enzyme. Carriers have about half as much hex A as non-carriers, but the carrier is not affected by Tay-Sachs and shows no symptoms. The blood sample can also be used for DNA-based genetic testing to look for known changes (mutations) in the hex A gene that causes Tay-Sachs.

Genetic testing is strongly recommended for people from high-risk populations, including:

• People descended from eastern and central European Jewish communities (Ashkenazi Jews). Among the Ashkenazi Jewish population, Tay-Sachs occurs in 1 in 2,500 to 3,600 births. An estimated 1 in 30 Ashkenazi Jews are carriers of the Tay-Sachs gene.
• People from certain French-Canadian communities of Quebec
• People from the Cajun community of Louisiana.

The Mayo Clinic Department of Medical Genetics has experience and expertise in genetic counseling and genetic testing for Tay-Sachs disease.