Tay-Sachs Essays -- Health Medical Medicine Biology Essays

Tay-SachsAbstract Tay-Sachs is a disease caused by a mutation to the constituent which codes for Hex A. Without Hex A, a cell cannot degrade GM2 ganglioside into GM3 ganglioside. This results in a build up of gangliosides in lysosomes of neurons. The result is varying degrees of mental deterioration. immature DNA-based screening is currently being developed to replace the enzyme-based screening techniques that have been used since 1969. This will not only speed up the diagnosis, but in like manner allow for earlier detection of Tay-Sachs by using the parents genotypes. Introduction Tay-Sachs disease is one of three autosomal recessive, lysosomal storage disorders, collectively know as the GM2 gangliosidoses. They result from accumulation of GM2 ganglioside in lysosomes, primarily of neurons. The clinical symptoms of Tay-Sachs vary from infantile lethal neurodegenerative disease to less severe adult incursion forms. The latter are often characterized by motor neuron impairments. T he recognition of the high incidence of this disease among Ashkenazi Jews and the identification of the deficiency of hexosaminidase A as the basal defect were essential findings leading to the establishment of mass carrier screening programs for this disease 2. Recently, research has focused on the DNA-based diagnostics that are anticipated to tactical manoeuvre a role in future carrier screening programs 1. GM2 ganglioside hydrolysis The lysosomal hydrolase, beta-hexosaminidase, occurs predominantly in two forms, hexosaminidase A (Hex A) and hexosaminidase B (Hex B). Hex A is comprised of one of import and one beta subunit while Hex B is comprised of two beta subunits 3. While both subunits contain similar active sites, only the important subunit can hydrolyze GM2 gan... ... Gravel, R. (1990). The molecular basis of Tay-Sachs disease mutation identification and diagnosis. Clin. Biochem. 23409-415. 2. Navon, R., Proia, R. (1991). Tay-Sachs disease in Moroccan Jews gash of a p henylalanine in the alpha-subunit of beta--hexosaminidase. Am. J. Hum. Genet. 48412-419. 3. Gray, R.G.F., Green, A., Rabb, L., Broadhead, D.M., Besley, G.T.N. (1990). A case of the B1 variant of GM2-gangliosidosis. J. Inher. Metab. Dis. 13280-282. 4. Meier, E., Schwarzmann, G., Furst, W., Sandhoff, K. (1991). The human GM2 activator protein. J. Biological Chem. 2661879-1887. 5. Mahuran, D.J. (1991). The biochemistry of HEXA and HEXB gene mutations causing GM2 gangliosidosis. Biochimica et Biophysica Acta. 109687-94. 6. Robbins, S., Ranzi, R., Kumar, V., (Eds). (1984). Pathologic Basis of Disease. Philadelphia, PA Saunders Co. 142-145.