[Juvenile GM2 gangliosidosis with progressive spinal muscular atrophy onset].
GM2 gangliosidosis are caused by a beta-hexosaminidase A enzyme deficiency. Mutations in the gene leaving residual enzyme activity give rise to juvenile and adult forms of the disease which have a great clinical heterogeneity. We report three cases which have been considered for some time as Kugelberg-Welander disease. beta-hexosaminidase A was determined with the sulfated synthetic substrate, 4-méthylumbelliferyl-N-acetylglucosamine 6-sulfate (4-MUGS), which allowed the diagnosis. Two of these cases from one family had normal values of hexosaminidase A in serum as found in the B1 variant. Compound mutations were detected. The B1 variants had a classical B1 mutation (G533-->A) and a new mutation located on exon 11. The patient of the second family had the classical mutation of adult GM2 gangliosidosis (Gly269-->Ser) and a new mutation on exon 1, at the initiation codon.
Rondot
P
P
Service de Neurologie, CHU Bicêtre, Le Kremlin-Bicêtre.
Navon
R
R
Eymard
B
B
Fardeau
M
M
Turpin
J C
JC
Lefevre
M
M
Bathien
N
N
Wu
Y
Y
Baumann
N
N
D000328:Adult; D005260:Female; D014644:Genetic Variation; D006579:Heterozygote; D054818:Hexosaminidase A; D006801:Humans; D008297:Male; D009134:Muscular Atrophy, Spinal / Q000209:etiology*; D009154:Mutation; D012497:Sandhoff Disease / Q000175:diagnosis* / Q000201:enzymology / Q000235:genetics; D001619:beta-N-Acetylhexosaminidases / Q000032:analysis / Q000235:genetics
D054818:Hexosaminidase A; D001619:beta-N-Acetylhexosaminidases