Tay-Sachs Disease Essay, Research Paper
Tay-sachs disease is perhaps a very dramatic disease because it strikes most keenly at small children and babies. The disease is very rare and fatal. Tay-sachs is a genetic disorder in which harmful amounts of fatty lipids, known as ganglioside GM2, is built up in the nerve cells in the brain. Infants who with Tay-sachs disease, who are not carriers, appear to develop normally for the first few months since their birth, but as the nerve cells become swollen with the fatty material, a severe decline of mental and physical abilities occurs. The child then becomes deaf, blind, and unable to swallow.
Soon, muscles begin to decay and paralysis takes effect. Eventually, the infant will die.
The first recorded case of Tay-sachs disease was described by Warren Tay, a British opthalmalogist, in 1881. In 1887, the American neurologist Barnard Sachs,described the neurology of Tay-sachs disease. Because these two men made such important contributions, as well as the earliest, to Tay-sachs disease, the disease was named after them.
Tay-sachs has infected millions of people since its discovery. The most common groups affected by Tay-sachs are Eastern and Central European Jews,some French-Canadians, the Irish, and some groups of Cajuns. The general carrier ratio for TSD is 1:250, or 0.4%.
Tay-Sachs is a recessive disorder, it is transmitted through the genes in the same way as eye color is passed from parent to child. Even though it is an inherited condition, most families are not aware that they carry genes for a disease until the birth of an affected child. Children with Tay-Sachs are most often born to parents with no family history of the disease. A recessive condition like Tay-Sachs results when a child inherits two copies of an altered gene, one from each parent. Both parents must be carriers of the same recessive disease gene in order for any of their children to be affected. Carriers themselves are not actually inflicted with the disease, and being a carrier does not affect the mother or father physically, mentally, or in any other way. High-risk couples, in which the man and the woman are carriers of the same genetic condition, have a 25% chance with each pregnancy of conceiving a child with that condition. There is a 50% chance of producing a child who is a carrier like the parents and a 25% chance that the child will be neither a carrier nor affected with the disease. If only one parent is a carrier, there is no chance of producing a baby with a recessive disease. There is, however, a 50% chance in each pregnancy that the child will be a carrier.
Tay-Sachs is an X-linked condition. An X-linked condition occurs when a person has a mutation in one of the genes on the X chromosome. X-linked conditions usually affect males more often and more severely than females, because females with a mutation in a gene on the X-chromosome usually have a non-mutated gene on their other X-chromosome, which can counteract for the mutation. Females with a mutation in a gene on one X chromosome and a normal copy of the gene on the other X chromosome carriers.
When a baby is infected with Tay-Sachs disease it appears normal and healthy,but usually symptoms begin to appear at 4-6 months since its birth.Early signs of the disease are when a baby gradually stops smiling, crawling, turning over, loses its ability to grasp things and to reach out, and eventually becomes blind, paralyzed, and unaware of its surroundings. Usually within 3-5 years of the infant’s life, death occurs.
The cause of death, and the effect Tay-Sachs has on the body is the lack of an enzyme known as hexosaminidase A, also known as hex A. This lysosome enzyme is needed to break down certain fatty substances, lipids, in the brain and nerve cells. Without this enzyme these substances build up and gradually harm and destroy brain and nerve cells, until the whole central nervous system breaks down and stops working. These enzymes are especially needed in the early stages of life, when the brain is first developing.
There is no cure for TSD as of yet, but research on the disease and possible cures has been done throughout the world. TSD most often appears in families with no prior history of the disease. The TSD gene can be carried without being resolute through many generations. Today, safe and reliable carrier testing is available to identify Tay-Sachs carriers. Testing can identify carrier couples who are at risk for bearing a child with TSD,before a TSD positive child is born. With this information, couples can look into the various options that will let them protect their families from this disease.A blood test can distinguish Tay-Sachs carriers from non-carriers. Blood samples can be analyzed by either an enzyme test or DNA studies. The enzyme test is a biochemical test that measures the level of Hex-A in a person’s blood. Carriers have less Hex-A in their body fluid and cells than non-carriers, but babies with Tay-Sachs disease have a complete absence of Hex-A in their cells. The biochemical test is able to detect all Tay-Sachs carriers of all ethnic backgrounds.
Although there is no cure for TSD, there are several revention methods for the disease, which gives hope to those who are carrier, but would like to bring a family into the world. Hopefully, further study and research of Tay-Sachs will lead to a cure one day, and TSD will no longer be a deadly factor for infants, and bring hope to their parents.