GM1 Gangliosidosis – Type II (Infantile Form)
Etiology and Pathogenesis
Enzyme deficiency results in accumulation of GM1 gangliosides in the central nervous system (especially the basal ganglia) and galactosyl oligosaccharides. Keratan-sulfate degradation products accumulate in somatic cells (visera). With type II, the deposition of GM1 gangliosides is less extensive than with type I. Deposition of substances in the peripheral tissues is less extensive than in type I, more than in III.
Key Symptom Images
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| Dorsolumbar kyphoscoliosis |
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Dystonia |
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Image Credits: Kyphosis courtesy of Ram Chadda, MS. Clinical Description and Progression/Prognosis  Later onset (6-20 months) Slower course Ataxia usually the initial symptom, followed by choreoathetoid movements Bony abnormalities (but milder than type I) Death occurs at 3-10 years of age Inheritance pattern: autosomal recessive Incidence (all types): generally unknown, but unusually high incidence of 1 case per 3700 live births has been reported in the population of Malta. [1] Diagnosis: enzyme assay Conditions with similar presentations: I-Cell Disease (Mucolipidosis Type II); Mucolipidosis Type I (Alpha-Neuraminidase Deficiency-Sialidosis); Mucopolysaccharidosis Type I (Hurler) Management: no disease-specific treatment available Other medical care: symptom management
Psychomotor retardation Normal development during 1st year of life Ataxia, followed by choreoathetoid movements Generalized moderate muscular weakness with hyper-reflexia Hypotonia leading to progressive spasticity and decerebrate rigidity Loss of speech Dulling of the sensorium Lack of socialization Lethargy Severe mental retardation Tonic-clonic seizures (beginning after 16 months of age) Optic atrophy leading to blindness Nystagmus Strabismus Recurrent bronchopneumonia Back to categories
References 
1. Tegay, David. “GM1 Gangliodosis”. www.emedicine.com/ped/topic2891.htm Accessed August 2004. |
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