Tay-Sachs Disease

Fatal Genetic Disorder

What is Tay-Sachs?

Tay-Sachs is a single gene mutation in which fatty acids, known as gangliosides fail to break down inside the individual's brain cells. This happens due to failing activity of a vital enzyme known as beta-hexosaminidase A. The inefficiency of the beta-hexosaminidase A is because of a missing gene on Chromosome 15, known as the HEXA gene. Without the HEXA gene gangliosides rapidly group inside the individual's brain cells and tissues. Due to the grouping of gangliosides in the individual's brain, the nervous system is gradually destroyed.

Inheritance

Tay-Sachs disease is extremely harmful and has taken the roll as one of the rarest, yet most fatal genetic disorders. In order to inherit Tay-Sachs disease an individual must have two parents that are carriers of the disorder. In order to be a carrier of the disorder, an individual must inherit one recessive allele, and in order to have Tay-Sachs, the individual must inherit two recessive alleles. Gender does not play any role in the inheritance of Tay-Sachs so therefore Tay-Sachs is an autosomal recessive disease. However, even if both parents are carriers of Tay-Sachs, there is still a 75% chance of the offspring being healthy and a 25% of the offspring being affected. The disease can occur in all people, but usually seems to occur in French Canadians, Louisiana Cajuns and Ashkenazi Jews. Those groups have a carrier rate of about 1/27, while other groups usually have a carrier rate of 1/250.

Effects

As you know, Tay-Sachs has a massive effect on the inheritor's nervous system and a nervous system is what carries out all functions of the body. So as the nervous system is destroyed, the individuals starts to develop unresponsiveness, inability to swallow, increased reaction to noise, blindness, and deaf. These symptoms are first seen around 6 months of age. As the individual ages the disease becomes more and more effective, making the individual less responsive to his or her surrounding environment. The individual eventually dies around the age of 4 or 5 in which their brain can no longer function.

History of Tay-Sachs

Tay-Sachs disease was first discovered and described in 1881 by ophthalmologist, Warren Tay, who had noticed a patient with a "cherry-red spot" on the retina of their eye. Then in 1887, the cellular changes and ethnical trends of Tay-Sachs were described by Bernard Sachs. About a hundred years later, in 1969, doctors, Shintaro Okada and John S. O'Brien published the discovery of the HEXA gene that is the soulful cause of Tay-Sachs.

Treatment, Tests, and Research

Sadly, there is no treatment to slow or prevent Tay-Sachs disease, however there is tons of undergoing research to discover a cure. One of the types of research that is being done is gene therapy. Researchers and scientists have found that gene therapy cures Tay-Sachs mice and greatly improves the condition of Tay-Sachs cats. Another possible treatment is using Pyrimethamine to increase enzyme activity, which would be able to prevent the gangliosides building up in the child's brain. Other possible and upcoming treatments include, substrate inhibition, work with stem cells, and bone marrow transplant.


Although there is no current cure for Tay-Sachs, enough research has been done so we can predict the disease. A test that is performed to see if an individual has Tay-Sachs is by looking at the retina of their eye, in which if the individual has Tay-Sachs they would have a cherry-red spot. To see if an upcoming child has a chance of inheriting Tay-Sachs, a blood test can be performed to measure the activity level of the beta-hexosaminidase A. Beta-hexosaminidase A is one of the substances in the brain cell, whose absence causes Tay-Sachs. As you can see, many groups of people are working to help Tay-Sachs patients and their families. Groups such as 'Genetic Alliance' and 'National Tay-Sachs and Allied Diseases Association' have put forth tons of money and effort assisting Tay-Sachs patients and helping to find a cure.