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Tay-Sachs Disease

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Description Tay-Sachs disease, (also known as GM2 gangliosidosis or hexosaminidase A deficiency), is a fatal autosomal recessive genetic disorder caused by insufficient activity of the enzyme beta-hexosaminidase A. It is very rare, found more prevalently among certain populations, like those with Eastern European, (Ashkenazi Jewish) heritage (Bethesda, 2014), and usually results in death by the age of four. The purpose of this essay is to illustrate the pathology and inheritance patterns of this genetic disorder, and provide the molecular base, prognosis, and possible treatments. The specific enzyme beta-hexosaminidase A is responsible for catalyzing the biodegradation of acidic fatty material in the brain and spinal cord known as gangliosides. …show more content…

The enzyme hexosaminidase is a crucial hydrolytic enzyme found in the lysosomes. When this enzyme no longer functions properly, lipids accumulate in the brain and cause interference with normal mental processes. Simple blood tests can determine presence of Tay-Sachs due to measurement of the levels of activity for hexosaminidase. The hydrolysis, (or breakdown) of the gangliosides requires three proteins: two of which are subunits of the enzyme hexosaminidase A, and the other being a small glycolipid transport protein that acts as a substrate (catalyst) for the enzyme. Deficiency in any of these proteins can lead to abnormal ganglioside storage, primarily in the lysosomes of neurons. Tay-Sachs disease occurs because of a mutation like this, either inhibiting or deactivating this process. The mutation occurs not at the active site, but instead because of incorrect function of intracellular transport. Infants with the disease Tay Sachs usually appear normal and healthy until three to six months of age. At this time, their development usually begins …show more content…

Warren Tay, an English physician who first described the symptomatic cherry-red eye in 1881 (Edelson, 1997). Research later in the 20th century illustrated that Tay-Sachs disease is a genetic disorder caused by a mutation in the HEXA gene on chromosome 15. Many other HEXA mutations have been discovered since then, including different mutations within different populations. Being an autosomal recessive disorder, for an individual to exhibit symptoms it is required to have two Tay-Sachs alleles affected, meaning that when both parents are carriers, the offspring have a 25% of being affected. This disease has shown to be prevalent in certain populations in recent years. Those of Ashkenazi Jewish descent are one of these populations, being more prone to the infantile form of Tay-Sachs disease, caused by a base pair insertion leading to the mutation. More research has led us to believe that compound heterozygosity is ultimately responsible for the disease’s variability among different populations. Those who are heterozygous carriers tend to exhibit abnormal enzyme activity but never show true disease symptoms. This is due to the dominance phenomenon, and with Tay-Sachs being recessive autosomal, it requires

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