from Part VIII - Major Human Diseases Past and Present
Published online by Cambridge University Press: 28 March 2008
Tay-Sachs disease (TSD) is the best known of the sphingolipidoses, a group of genetic disorders that includes Niemann-Pick disease, Gaucher’s disease, and others. Specifically, TSD is GM2 (beta) gangliosidosis, an autosomal recessive disease with complete penetrance. Affected individuals (recessive homozygotes) produce virtually no functional hexosaminidase A (hex A), an enzyme necessary for normal neurological development and function. TSD is very rare in most populations, but is, overall, about 100 times more prevalent among Ashkenazi Jews. This indicates that the TSD gene frequency is about 10 times higher in the Ashkenazi Jewish population. Persons with the disease usually show clinical symptoms of neurological degeneration by 6 months of age. Their condition steadily deteriorates, and they seldom live beyond the age of 4 years. There is no cure, but heterozygous “carriers” of the defective gene can be identified by clinical test, and amniocentesis can detect an affected fetus.
History
The British ophthalmologist Warren Tay (1881) first reported some of the early clinical signs of TSD. In the United States, Bernard Sachs (1887) further documented the clinical course and pathology of the disease he later called “amaurotic family idiocy” (Sachs 1896). 1896). It was Sachs who first noted the familial nature of the disease, and its seemingly exclusive occurrence in Jewish families. However, reports were soon made of non-Jewish cases. D. Slome (1933) was the first to survey the literature on the population characteristics of TSD and confirmed the disease’s autosomal recessive mode of transmission as well as the TSD gene’s higher frequency among Jews.
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