APA Dictionary of Psychology

an autosomal recessive disorder primarily affecting Ashkenazi Jews of central and eastern European origin. The disease is due to a deficiency of the enzyme hexosaminidase A, resulting in the accumulation of G_M2 gangliosides in all tissues (see gangliosidosis). This process gradually destroys the brain and nerve cells by altering the shape of neurons. Development is normal until the 6th month of infancy, after which there is a deterioration of motor, visual, and cognitive abilities. Death usually occurs between 3 and 5 years of age. Also called GM2 gangliosidosis. [Warren Tay (1843–1927), British physician; Bernard Sachs (1858–1944), U.S. neurologist]