The most common of the lipid storage diseases, Tay-Sachs disease results from a congenital deficiency of the enzyme hexosaminidase A. It’s characterized by progressive mental and motor deterioration and is usually fatal before age 5, although some adolescents and adults with variations of hexosaminidase A deficiency have been noted.
Tay-Sachs disease (also known as GM2 gangliosidosis) is an autosomal recessive disorder in which the enzyme hexosaminidase A is virtually absent or deficient. This enzyme is necessary for metabolism of gangliosides, water-soluble glycolipids found primarily in central nervous system (CNS) tissues. Without hexosaminidase A, accumulating lipid pigments distend and progressively destroy and demyelinate CNS cells.
Tay-Sachs disease strikes persons of Eastern European Jewish (Ashkenazi) ancestry more often than the general population, occurring in about 1 in 2,500 live births in this ethnic group. About 1 in 25 Ashkenazi Jews are heterozygous carriers.