Tay Sachs Disease – How the Jewish Overcome the Condition
Sachs disease or TSD is a serious genetic disorder, which is common to children that result in the destruction of the nervous system. The absence of the vital enzyme known as hexosaminidase-A or Hex-A is the main cause of this disorder.
Without this enzyme, a fatty substance known as GM2 ganglioside accumulates in cells, particularly in the brain cells. If the accumulation continues, it causes progressive damage to the cells.
What is Tay – Sachs disease?
The condition starts in the early stage of pregnancy. But, the manifestation will only be observed when the infant is about six months of age. At two years of age, children with Tay-Sach experience recurrent seizures and their mental function decrease. The infant will not be able to crawl, sit, reach out or turn over.
As the condition progresses, the child may become cognitively impaired, non-responsive, blind and paralyzed. At the age of 3 or 4 years old, the nervous system is badly affected that might lead to death by the age of five.
The Late-Onset Tay-Sachs disease is a very rare form of Tay-Sachs that affects adults and may cause intellectual and neurological impairment.
Ashkenazi Jews Are At High Risk of Having Tay-Sachs
Although anyone can be a carrier of this disease, the cases are most prominent among the Ashkenazi Jewish descent. One in every 27 Jews is a carrier of the Tay-Sachs disease gene.
At present, the cure has not yet discovered for this disease. But, researchers are doing their best to find a cure. To provide the needed HEX-A, the scientists are studying the enzyme replacement therapy. Another option is the bone marrow transplantation, but it is not successful in slowing or reversing the damage to the CNS in babies with the disease.
Gene therapy is yet another therapy that scientists transfer a normal gene into cells as a replacement for an abnormal gene. As compared to the first approach, this one has a better future for infants suffering from Tay-Sachs disease.
How to Detect a Tay-Sachs Carrier
A blood test can easily determine if a person is a Tay-Sachs carrier or not. The test analyses the DNA or enzyme assay. To measure the level of HEX-A, a biochemical test enzyme assay is done. A Tay-Sachs Carrier has less Hex-A in their cells and fluid as compared to non-carriers.
The DNA-based testing looks for mutations or modification in the gene that codes for Hex-A. Over 50 different mutations in this gene were identified since 1985. But there are still some mutations that are not yet identified. The test done in Ashkenazi Jewish population shows that 95% are a carrier and around 60% of carriers are found in the entire population.
If in case both parents are carriers, they can seek help with a genetic counsellor for assistance in deciding if they can conceive or have the fetus checked for Tay-Sachs. The number of cases of Tay-Sachs has significantly reduced thru extensive carrier testing of Ashkenazi Jews. Today most cases are found in populations thought not to be at high risk.