TAY-SACHS DISEASE

What Is It?

• fatal genetic disorder that progressively destroys the nervous system
• caused by the absence of a vital enzyme called hexosaminidase-A (Hex-A)
• Without Hex-A, a lipid called GM2 ganglioside accumulates abnormally in cells
• Carriers have a 50 percent chance of passing on the defective gene to their children

DIAGNOSIS

• A simple blood test can identify Tay-Sachs carriers
• Blood samples can be analyzed by either enzyme assay or DNA studies
• enzyme assay is a biochemical test that measures the level of Hex-A in a person's blood
• Carriers have less Hex-A in their body fluid and cells than non-carriers
• The current tests detect about 95 percent of carriers of Ashkenazi Jewish background

WHAT IT DOES

• destructive process begins in the fetus early in pregnancy
• a baby appears normal until about six months when its development slows
• By about two years of age, most children experience recurrent seizures and diminishing mental function
• Eventually, the child becomes blind, cognitively impaired, paralyzed and non-responsive
• By the time a child is 3 or 4 years old, the nervous system is so badly affected that death usually results by age 5