GM1 Gangliosidosis – Type I (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 I, the deposition of GM1 gangliosides is extensive (more so than with the other two types). Deposition of substances in the peripheral tissues is also more extensive in type I (than in II and III).
Key Symptom Images
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| Dorsolumbar kyphoscoliosis |
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Hepatosplenomegaly |
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Cherry-red macular spots |
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Image Credits: Kyphosis courtesy of ram Chadda, MS. Cherry-red macular spots courtesy of Jay M. Haynie, OD.
Clinical Description and Progression/Prognosis  Early onset (newborn) Rapid progression Marked by severe bony abnormalities Death occurs at 6-24 months of age Inheritance pattern: autosomal recessive Incidence: 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
Noted from birth Severe psychomotor retardation Hypotonic; decerebrate rigidity Hypoactive with poor grasp Usually never able to sit or crawl Generalized hyperreflexia, poor muscle strength Mental retardation (severe) Tonic-clonic seizures (after 1 year of age) Poor appetite, weak suck Failure to thrive, growth retardation Hepatomegaly / hepatosplenomegaly Umbilical and inguinal hernias Back to categories Facial: Frontal bossing Depressed nasal bridge Large low-set ears Coarse facial features Gum hypertrophy Mild macroglossia Facial edema Other: Dorsolumbar kyphoscoliosis Stiff joints with flexion contractures at elbows and knees Diffuse corneal clouding Cherry-red macular spots (in 50% of cases) Retinal vascular tortuosity and hemorrhage Optic atrophy; early blindness Nystagmus Strabismus Back to categories Recurrent bronchopneumonia Paroxysmal atrial tachycardia Cardiomegaly Scrotal edema Thick, hirsute, rough skin Back to categories
References 
1. Tegay, David. “GM1 Gangliodosis”. www.emedicine.com/ped/topic2891.htm Accessed August 2004. |
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