Background
Tay-Sachs disease is a deadly disease of the nervous system passed down through families. It occurs when the body lacks hexosaminidase A, a
protein that helps break down a chemical found in nerve tissue called gangliosides. Without this protein, gangliosides, particularly ganglioside GM2,
build up in cells, especially nerve cells in the brain.
Tay-Sachs disease is caused by a defective gene on chromosome 15. When both parents carry the defective Tay-Sachs gene, a child has a 25% chance of
developing the disease. The child must receive two copies of the defective gene -- one from each parent -- in order to become sick. If only one parent
passes the defective gene to the child, the child is called a carrier. He or she won't be sick, but will have the potential to pass the disease to
his or her own children.
Tay-Sachs has been classified into infantile, juvenile, and adult forms, depending on the symptoms and when they first appear. Most people with
Tay-Sachs have the infantile form. In this form, the nerve damage usually begins while the baby is still in the womb. Symptoms usually appear when the
child is 3 to 6 months old. The disease tends to get worse very quickly, and the child usually dies by age 4 or 5.
(Source: PubMed Health)
Imagine that you're going to have your first child. The mother - perhaps yourself, perhaps your wife (whichever is appropriate) - is in the beginning
of her second trimester. Coincidentally, you and your spouse recently had routine exams when the doctor says he tested you both and found that you are
both carriers of the Tay-Sachs gene.
There is a one in four chance that you may pass Tay-Sachs disease to your child. Do you opt to test the fetus for Tay-Sachs disease?