Tay-Sachs Disease
Kids with Tay-Sachs
Symptoms: same as early onset Tay-Sachs but the progress of the disease is slower. Kids with early onset Tay-Sachs start showing symptoms at age five. They die by about age 15.
Overview
Tay-Sachs is a neurological disorder. Normally, the gene HEX A codes for the alpha subunit of the hexosaminidase A protein which prevents the buildup of GM2 gangliosides. In a person with Tay-Sachs, HEX A is mutated so that gangliosides build up. When gangliosides accumulate they damage the normal function of the neurons. The build up of GM2 gangliosides is poisonous and eventually leads to death.
Cause
Tay-Sachs is inherited when you receive two severely mutated HEX A genes, one from each parent. Tay-Sachs Disease is a recessive disorder, so you only get it if you have two recessive genes.
Treatment
There is no effective treatment or cure of Tay-Sachs. Researchers have successfully given mice a shot of gene therapy that delivered a beneficial gene to the entire brain. If these results can be duplicated in people, it may cure Tay-Sachs disease, but it hasn't been done yet. Patients with adult onset Tay-Sachs are provided with wheelchairs because of their muscle weakness.
Testing
A blood test can be taken to show whether or not you are a carrier of the disease. This test has significantly reduced the number of Tay-Sachs patients in the United States. To test babies for Tay-Sachs, doctors draw blood from the baby's foot and then isolate the white blood cells from the other blood cells. Then they look directly at the baby's DNA.
Adult onset
Adult onset Tay-Sachs starts lots later in life than the other forms of Tay-Sachs disease. Symptoms: muscle cramps, behavioral changes, and slurred speech. This is the mildest form of Tay-Sachs disease. In adult onset Tay-Sachs you can live a normal lifespan if given the proper medical care, but you will still die at about the age of 60 because of Tay-Sachs. Some adult onset patients have mental retardation and psychotic episodes.
Juvenile
Babies that are born with Tay-Sachs look totally normal and happy when they are born. The only sign that they have Tay-Sachs is a cherry red spot in the retina of the eye.
Cause of Tay-Sachs Disease
Doctors Tay and Sachs discovered Tay-Sachs in the 18th century by noticing a cherry red spot in the retina of patients with similar symptoms. Tay-Sachs Disease is caused by a mutation in the HEX A gene on chromosome 15.
Types
Early onset Tay-Sachs Juvenile Tay-Sachs Adult onset Tay-Sachs
Early onset
Early onset Tay-Sachs starts when babies are born. Symptoms: not gaining or losing mental and motor skills, paralysis, and death by age five.
Trying to Cure
Scientists tried to use enzyme replacement therapy to replace the HEX A, but they found out that once replaced the enzyme can't reach the brain. Even if you could get the HEX A to the brain, you would need to get the HEX A into the neurons to fix the buildup of GM2 gangliosides. Ideally scientists would like to be able to cure Tay-Sachs by replacing the mutated gene, but they are still a long way away from being able to do that.
Frequency
Tay-Sachs is most common among eastern European Jews. 1 in every 27 Jews in the US is a carrier of Tay-Sachs Disease. French Canadians and Cajuns are also frequent carriers of the disease with a 1 in 27 rate. In the general population 1 in 250 people are carriers of Tay-Sachs.
