Tay-Sachs Disease

Tay-Sachs is an autosomal-recessive genetic disorder for which there is no treatment or cure. It is caused by a lack of an enzyme called Hex-A, or hexosaminidase A. This enzyme is necessary for the break down of fatty wastes in the brain's nerve cells. When there is an absence of this enzyme, the fatty waste substance (GM2 ganglioside) builds up in the cells, causing damage to the nervous system to point at which the individual with Tay-Sachs dies. The Tay-Sachs causing gene is found on chromosome 15. Tay-Sachs is an inherited disease, for which anyone can be a carrier. About 1 out of every 250 people in the population are carriers for Tay-Sachs. If both parents of a child are carriers, there is a 25% chance that the child will be born with Tay-Sachs. Certain populations, such as French Canadians and Ashkenazi Jews, appear to have increased risk of being carriers of Tay-Sachs.

There are three forms of Tay-Sachs: infantile, juvenile, and late onset. Only one of the forms can be present within one family. The most common form is classic infantile Tay-Sachs, for which symptoms develop around 6 months of age, causing the affected individual to die by the age of 5. The symptoms involve a slowing down of development, as mental and motor capabilities decrease. Eventually, the child becomes unresponsive to their environment. This disease is diagnosed either by a blood test to check the child's Hex-A levels or by identifying a cherry-red spot on the child's retina, which is classic for infantile Tay-Sachs.


For more information look at these articles that I referenced: http://www.ntsad.org/index.php/tay-sachs
http://www.tay-sachs.org/taysachs_disease.php