GM2 gangliosidosis II(Sandhoff disease) is a lysosomal storage disease due to deficiency of beta-hexosaminidase activity, transmitted by mode of autosomal recessive. Clinical features are so variable, ranging from infantile onset resulting death before 4 years, to subacute or chronic forms with more slowly progressive neurologic condition. We experienced a case of GM2 gangliosidosis II in a 14 months old male who had developmental deterioration and seizures, so we report and review the related literatures.
beta-N-Acetylhexosaminidases ; Gangliosidoses, GM2* ; Hexosaminidases ; Humans ; Infant ; Lysosomal Storage Diseases ; Male ; Seizures

Sphingolipidoses are a subgroup of lysosomal storage disorders. They are characterized by relentless progressive storage in affected organs and concomitant functional impairments. No overall screening procedure for these disorders is available. Their course and appearance, however, are usually characteristic and, together with relevant technical procedures such as magnetic resonance imaging (MRI), clinical neurophysiology, ophthalmologic examination, etc., a provisional diagnosis can be made, after which enzymatic diagnosis can close the gap in the diagnostic process. Subgroups of sphingolipidoses are grouped together, such as disorders with prominent hepatosplenomegaly (Niemann-Pick A, B and Gaucher disease) and disorders with central and peripheral demyelination (metachromic leukodystrophy and Krabbe disease). Farber disease and Fabry disease are unique in themselves. The last decade has seen hopeful progress in therapeutic strategies, especially for Gaucher disease. Therefore, emphasis of this review has been placed on these new developments.
Demyelinating Diseases ; Diagnosis ; Fabry Disease ; Farber Lipogranulomatosis ; Gangliosidoses, GM2 ; Gangliosidosis, GM1 ; Gaucher Disease ; Hope ; Leukodystrophy, Globoid Cell ; Magnetic Resonance Imaging ; Mass Screening ; Neurophysiology ; Niemann-Pick Diseases ; Sphingolipidoses*

OBJECTIVETo study the molecular mechanism of GM(2) gangliosidosis.

METHODSThe skin fibroblasts from 4 patients with GM(2) gangliosidosis were subjected to culture. Enzyme activities assay, Western blot and immunocytochemical analysis were performed using the cultured fibroblasts.

RESULTSThe hexosaminidase (Hex) activities of 4 patients with GM(2) gangliosidosis were significantly decreased. The activities were 12% 3% 15% and 6% of control values, respectively. Western blot analysis indicated that the amount of Hex mature alpha- and beta- subunits (alpha m, beta m) was decreased in cells from patients 2 and 3, but only decreased alpha m was found in patient 1 and both alpha m and beta m were normal in cells from patient 4. Immunocytochemical analysis revealed the accumulated GM(2) ganglioside in cells from patients 1-4.

CONCLUSIONThe pathogenesis of GM(2) gangliosidosis was associated with deficiency of Hex alpha m and beta m and GM(2) activator caused by HEXA, HEXB and GM(2)A gene mutations.

Adult ; Blotting, Western ; Cells, Cultured ; Child, Preschool ; Female ; Gangliosidoses, GM2 ; enzymology ; pathology ; Hexosaminidase A ; Hexosaminidase B ; Humans ; Infant ; Male ; Protein Subunits ; metabolism ; beta-N-Acetylhexosaminidases ; metabolism