Tay-Sachs disease is a rare inherited disorder caused by the progressive destruction of the nerve cells in the brain and spinal cord. People with Tay-Sachs disease make a defective version of the hexosaminidase A enzyme (encoded by the HEXA gene), which leads to the accumulation of a substance called GM2 ganglioside that is toxic to cells in the brain and nervous system.
The most common form of Tay-Sachs disease becomes apparent during infancy. This severe infantile form results in rapid neurodegeneration and death by four years of age. Those with the adult-onset form, have a later onset and slower progression of the disease.
Take this test to find out if you are a carrier of a HEXA variant and are at risk of passing it to your children.
Tay-Sachs disease is caused by variants in the HEXA gene. This gene provides instructions for one component (the alpha subunit) of the beta-hexosaminidase A enzyme. Beta-hexosaminidase A is responsible for breaking down a fatty substance called GM2 ganglioside. An accumulation of GM2 ganglioside leads to the destruction of nerve cells and symptoms associated with Tay-Sachs disease.
Tay-Sachs disease is an autosomal recessive disorder, meaning that a person must inherit two defective copies of the HEXA gene for symptoms to occur. People who inherit just one defective HEXA gene are unaffected. However, they can pass on the defective variant to the next generation.
This test detects four genetic variants in the HEXA gene, which account for 99% of affected or carrier individuals of Ashkenazi Jewish or Cajun descent.
- rs387906309 (1278insTATC)
- rs147324677 (IVS12+1G>C)
- rs76173977 (IVS9+1G>A)
- rs121907954 (G269S)
Understanding your carrier status for these variants will help you understand the risk of passing a variant to your children.
The symptoms of the severe infantile form include:
- Developmental delays
- Muscle weakness
- Overreaction to loud noises
- Sudden muscle contractions causing severe twitches, jerks, and seizures
- Vision problems
- Unable to achieve new motor skills and begin to lose previously demonstrated skills
The symptoms associated with the adult-onset form vary from person to person. Some of these symptoms include:
- Mood changes
- Progressive muscle weakness and wasting
- Tremors and seizures
- Slurred speech
- Difficulty swallowing
- Involuntary muscle spasms
- Difficulties with movement
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Step 1: Sign up for a free DNA Access account.
Step 2: Upload your DNA markers to DNA Access.
Step 3: Log in to your account to access your results when they are ready.