How does Tay-Sachs disease primarily affect nervous system function?

Tay-Sachs disease primarily affects nervous system function by causing a deficiency in a specific enzyme called hexosaminidase A. This enzyme is crucial for the breakdown of gangliosides, which are complex lipids that accumulate in the nerve cells. In individuals with Tay-Sachs disease, the missing protein impairs the body's ability to metabolize these gangliosides properly, leading to their excessive buildup, particularly in the brain and spinal cord. As the gangliosides accumulate, they cause progressive damage to nerve cells, which manifests as neurological symptoms such as developmental delay, loss of motor skills, and eventually severe cognitive and physical decline. This accumulation and resulting cellular damage is the primary underlying mechanism through which Tay-Sachs affects nervous system function.