Final answer:
Beta-hexosaminidase A deficiency, GM2 ganglioside accumulation, and its prevalence among Ashkenazi Jews.
Step-by-step explanation:
Beta-hexosaminidase A deficiency, also known as GM2 gangliosidosis, is a genetic disorder that affects the metabolism of a lipid called GM2 ganglioside. This deficiency leads to the accumulation of GM2 ganglioside in various tissues, including the brain. It is particularly prevalent among Ashkenazi Jews. The deficiency of beta-hexosaminidase A enzyme, which is responsible for breaking down GM2 ganglioside, results in the neurological symptoms associated with this disorder.