Galactosialidosis
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Metabolic defect: 32-kilodalton protein deficiency
Other multiple enzyme deficiencies: mucolipidosis: type II, type III
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| Etiology and Pathogenesis
One of five conditions that account for the majority of cases of progressive myoclonus epilepsies. Deficiency of a 32-kilodalton protein that is essential for the catalytic activity results in deficiency of alpha-N-acetyl-neuraminidase and degradation of beta-galactosidase. Sialyloligosaccharides and sialylglycopeptides accumulate in lymphocytes, fibroblasts, bone marrow cells, Kupffer cells (liver), Schwann cells, and other cells.
Key Symptom Images Image Credits: Cherry-red macular spots courtesy of Jay M. Haynie, OD.
Clinical Description and Progression/Prognosis
A neurodegenerative disorder characterized by myoclonic seizures, tonic-clonic seizures, progressive neurologic dysfunction (dementia and ataxia), and cherry-red macular spots. May be considered a juvenile form of sialidosis. Inheritance pattern: autosomal recessive Incidence: unknown Diagnosis: enzyme assay Conditions with similar presentations: Sialidosis, Fabry Management: no disease-specific treatment available Other medical care: symptom management
 Initial: Myoclonic seizures - Generalized, affecting the extremities - Triggered by voluntary movement, touch, sound, smoking, menstrual cycle - Progressive, eventually leading to non-ambulatory Later: Tonic-clonic seizures - Ataxia - Mental deterioration leading to dementia - Hearing loss
Progressive loss of visual acuity Gradual loss of vision Coarse facial features Angiokeratoma corporis diffusum Back to categories
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