There are different tests that can be used to diagnose Tay-Sachs disease. An enzyme assay is standard for diagnosing this disorder. An enzyme assay is a test that measures the activity of an enzyme. Doctors take a blood sample and send it off to a lab where they measure the sample for hexosaminidase A activity. If this enzyme is low or absent, that means a person has Tay-Sachs disease.
Molecular genetic testing can also be used to confirm a diagnosis. These tests involve studying the HEXA gene for changes that cause the disorder. This can include sequence analysis, where a part or sequence of DNA within a gene is examined, or targeted mutation analysis, where the six most common mutations in the HEXA gene that cause Tay-Sachs disease are searched for, or deletion/duplication analysis, where missing or extra regions of DNA are looked for within a specific gene. Molecular genetic testing must be done at specialized laboratories.
There are more tests a doctor might perform when assessing someone for Tay-Sachs disease. These may be done to detect or assess specific symptoms. For example, an eye exam may reveal cherry red spots on the retina.
Talk to your doctor about what the results of these tests may mean in Tay-Sachs disease. To find a genetic medical professional nearby who can discuss information and testing, a listing of medical geneticists can be found at the American College of Medical Geneticists website and genetic counselors can be found on the National Society of Genetic Counselors website.
