TAY-SACHS DISEASE - A genetic disorder found in east European Jewish families which can result in early death. The genetic defect involves the deficiency of an enzyme (hexosaminidase) that is inherited as a recessive gene. Symptoms appear at age 3-6 months and include blindness, deafness, seizures, paralysis, dementia, decreased muscle tone, and growth retardation. There is no known treatment and most children usually die by age three.