GM2 gangliosidosis with hexosaminidase A and B defect: Report of a family with motor neuron disease‐like phenotype

Abstract

GM2 Gangliosidosis is an inherited dysmetabolic disease, characterized by accumulation of GM2 and GA2 gangliosides in neuronal as well as in non-neuronal tissues. Biochemically the disorder can be due either to a deficiency of hexosaminidase isoenzyme A (Tay-Sachs form) or isoenzymes A and B (Sandhoff variant) or to absence of the activator protein of the enzyme (Sandhoff and Christomanov, 1979). Infantile, juvenile and adult phenotypes are known. Recently patients with late-onset disease with amyotrophic lateral sclerosis-like or Kugebelg-Welander phenotypes or spinocerebellar ataxia have been described, and a large heterogeneity is increasingly being discovered (Johnson, 1981; Federico, in press).