Tay-Sachs disease is an inherited birth defect which first becomes noticeable at about four to six months of age when an otherwise healthy baby gradually ceases to smile, crawl, turn over, or reach out, and ultimately becomes blind and paralyzed. Death occurs at about the age of five years. Tay-Sachs disease is among a number of genetic disorders that result from the body's inability to produce lipid-degrading enzymes. Lacking these enzymes, lipids accumulate in the cells, resulting in kidney failure, enlargement of the liver and spleen, mental retardation, blindness, skeletal deformities, and, eventually, the shut-down of the entire nervous system.

Tay-Sachs disease was the first of its type to be studied, and was first recognized by the British ophthalmologist, Warren Tay (1843-1927) in 1881. Tay noticed a cherry-red spot on the retina of a one-year-old child who exhibited many of the signs of the disorder. The child...