Tay Sachs Essay, Research Paper
Tay-Sachs
Tay-Sachs disease is a genetic disorder that occurs in children. This disease causes their central nervous system to breakdown, which in turn is the basis for their death. The disease is named for Warren Tay and Bernard Sachs.
Tay-Sachs disease is caused by the absence of an enzyme called Hexosamindase A, which is referred to as Hex-A. The lack of this enzyme causes many metabolic problems for its host because it is necessary for breaking down wastes within the brain. The result of its absence is that it causes an increasing loss of coordination, a progressive inability to swallow, breathing difficulties, blindness, mentally retardation, paralysis, and finally death.
The enzyme known as Hex-A is extremely essential for a person to sustain life. This is due to the fact that Hex-A is needed for the body to break down a fatty waste substance found in brain cells. This fatty substance or lipid called GM2 ganglioside accumulates abnormally in cells, especially in the nerve cells of the brain. As wastes are constantly collected, there is a progressive damage to the cells. The destructive process begins in the fetus early in pregnancy, although the disease is not clinically apparent until the child is several months old. By the that time a child with the disease is three or four years old and the nervous system is so badly affected that life itself cannot be supported.
The information for the body to make the Hex A enzyme is contained in a gene which is found on chromosome number 15. There are two copies of chromosome number 15 in all the body cells and therefore two copies of the gene that codes for the enzyme necessary for correct brain function. If that gene is changed or mutated, which is what happens in the case of Tay-Sachs disease, the information contained in the gene, and therefore the child, is impaired.
The genetic error which is present in Tay-Sachs disease is a mutation on the 15th chromosome, which contains the enzyme Hexosamindase A. The enzyme is deleted and thus the child is unable to break down GM2 ganglioside within the brain.
Tay-Sachs is an autosomal recessive trait, meaning it is manifested in an individual through hereditary. As a result the only way that a child can have the disease is if both its mother and father are carriers of the recessive trait.
To date, there is no cure or effective treatment for Tay-Sachs. However, there is active research being done in many laboratories in the U.S. and around the world. The use of enzyme replacement therapy to provide the Hex-A has been explored. Bone marrow transplantation has also been attempted, but to date has not been successful in reversing or slowing damage to the central nervous system in babies.
The inheritance pattern of Tay-Sachs disease is autosomal recessive. In order for a child to inherit a recessive condition such as Tay-Sachs they must receive a recessive gene from both their father and mother. For this reason most children born with this disease come from a family without a history of Tay-Sachs. The parents are both simply carriers of the recessive trait therefore there is a 25% chance the child will be afflicted.
Many metabolic disorders plague people throughout the world, yet few are as terrible and devastating to a family as Tay-Sachs disease. This is because the disease comes with absolutely no warning to the child s healthy carrier parents. As soon as they find out their child is afflicted they must face the inevitable fact that he will die in 5 short years.
Bibliography
1. www.tay-sachs.org./whatisa.htm
2. www.noah.cuny.edu/neuro/neuropg.htm#taysachs.