Which condition is characterized by progressive destruction of nerve cells in infants?

Tay-Sachs disease is characterized by the progressive destruction of nerve cells, particularly in infants. This genetic disorder results from a mutation in the HEXA gene, which encodes an enzyme called hexosaminidase A. This enzyme is crucial for the breakdown of a fatty substance called GM2 ganglioside in nerve cells. When the enzyme is deficient or absent, GM2 ganglioside accumulates to toxic levels, leading to the degeneration of nerve cells.

Infants with Tay-Sachs typically appear normal at birth, but they begin to show signs of neurological deterioration by about six months of age. This deterioration manifests as a loss of motor skills, seizures, vision and hearing loss, and ultimately, it can lead to death by the age of 4 or 5 years. The catastrophic effects on the neurological system highlight the critical nature of the enzyme involved and the hereditary nature of the condition.

In contrast, the other options represent different conditions that do not involve such progressive and severe nerve cell destruction. Down syndrome is a chromosomal disorder, Fragile X syndrome primarily affects cognitive function and is a genetic condition linked to changes in the FMR1 gene, and autism is a neurodevelopmental disorder that affects communication and behavior but does not involve the