GM1 gangliosidosis

A genetic lipid storage disorder that is similar in certain respects to Hurler syndrome and Tay-Sachs disease but which affects both the brain and the viscera (the internal organs). GM1 gangliosidosis causes skeletal deformities and exerts severe effects on the brain and internal organs. Death usually occurs by the age of 2. GM1 gangliosidosis is one of the classic lipid storage diseases. The gene responsible for it maps to chromosome 3. There is no treatment for the disease. It is also known as familial neurovisceral lipidosis and Landing disease (after the pioneering pediatric pathologist Ben Landing). See also Hurler syndrome and Tay-Sachs disease.

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an autosomal recessive disorder due to a deficiency of lysosomal β-galactosidase activity as a result of mutation in the GLB1 gene (locus: 21.33), with accumulation of ganglioside GM_{1>, glycoproteins, and keratan sulfate. It occurs as several forms, decreasing in severity with increasing age of onset. The infantile, or type I, form is characterized by onset at birth, severe retardation of mental and motor development, cerebral degeneration, dysostosis multiplex, hepatosplenomegaly, early blindness, coarse facies, edema, seizures, hypotonia, hyperacusis, dysarthria, and sometimes cherry-red macular spot; death occurs by the age of 2. The juvenile, or type II, form is characterized by onset between 6 and 20 months, accumulation of ganglioside GM1 in brain but not viscera, seizures, late blindness, spasticity, and ataxia; death occurs between 3 and 10 years of age. The adult, or type III, form is characterized by onset in the teens, spasticity, and dysarthria, with little intellectual impairment and survival into the third decade.}