Tay-Sach’s disease

Detterman One complication I wondered about, is exactly what is a deleterious mutation Many of these genes that in the homozygous state produce mental retardation, in the recessive state actually confer some reproductive advantage, even though they may lower IQ. There is evidence for phenylketonuria, for instance, and Tay Sach s disease. 

Cachon-Gonzalez, M. B., Wang, S. Z., Lynch, A., Ziegler, R., Cheng, S. H., and Cox, T. M., Effective gene therapy in an authentic model of Tay-Sachs-related diseases, Proc Natl Acad Sci USA 103 (2006) 10373-10378. 

Sandhoff s disease is due to a deficiency of the HexB gene. Clinical features are similar to those of Tay-Sachs disease. Late infantile, juvenile and adults variants have also been described. 

A-acetyl-)3-D-hexosaminides. The enzyme can also utilize A-acetylglucosides and A-acetylgalactosides as substrates. The associated human genetic disorders are known as Sandhoff s disease and Tay-Sachs disease. 

O Brien JS, Okada S, Chen A, Fillerup DL (1970) Tay-Sachs disease. Detection of heterozygotes and homozygotes by serum hexosaminidase assay. N Engl J Med 283 15-20... 

Lysosomal storage abnormalities, such as glycogenosis (Pompe s disease). Tay-Sachs, Krabbe s. Gaucher s, and Fabry s diseases, as well as melachromatic leukodystrophy, aspariylgiycosaminuria, and Niemann-Pick disease. Also included in this category are mucopolysaccharidoses. Hunter s, Scheie s, and Hurler s syndromes. 

Among its many other applications, DNA fingerprinting is widely used for the diagnosis of genetic disorders. Cystic fibrosis, hemophilia, Huntington s disease, Tay-Sachs disease, and sickle-cell anemia are among the many diseases that can be detected, enabling early treatment of an affected child. In addition, the U.S. Department of Defense now requires blood and saliva samples from all military personnel. The samples are stored, and DNA is extracted should the need for identification of a casualty arise. 

Figure 9.20 Degradation of sphingolipids. Lipid storage diseases are indicated by brackets as follows TS, Tay-Sachs ML, metachromatic leukodystrophy GG, generalized gangliosidosis G, Gaucher s disease NP, Niemann-Pick disease K, Krabbe s disease F, Fabry s disease. The sulfate residue on galactocerebroside is located on position 3 of the galactose residue. Note the sequential nature of the process if one step cannot take place, all subsequent steps cannot take place, either.

The ganglioside content of the brain of an infant with Tay-Sachs disease is greatly elevated. The concentration of ganglioside G is many times as high as normal because its terminal S -acetylgalactosamine residue is removed very... 

Tay-Sachs disease is the B-variant of GM2 gangliosidosis due to a-chain deficiency and to the subsequent deficiency of hexosaminidases A and S, buf wifh normal hexosaminidase B. Depending on fhe residual enz)me acfivify of /3-hexosaminidase, fhe onsef of symptoms may occur an)Twhere from late infancy to adulthood and are usually subclassifled into infantile (t) e 1)-, juvenile (type 2)-, chronic-, and adult-onset forms [33]. In type 1, the most common disease with a carrier frequency of 1 in 27 among Ashkenazi Jews [154], patients are normal at birth but then show s)mptoms, such as mild motor weakness, between 3 and 6 months, resulting in hypotonia, poor head control, decreasing attentiveness, and visual symptoms (cherry red... 

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