Tay Sachs genetic problem and solution

Tay-Sachs disease is typically found in people with certain ancestry, such as Eastern European Jews. A fatty substance in the brain destroys nerve cells.
Symptoms of slowed development usually appear around six months of age. Symptoms progress until they lead to death, often around age four.
There is no cure for Tay-Sachs disease, but research is ongoing.

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Please I don't understand Tay Sachs disease equation