TYPE-3 GM1 GANGLIOSIDOSIS - CLINICAL AND NEURORADIOLOGICAL FINDINGS IN AN 11-YEAR-OLD GIRL

An 11-year-old Japanese girl was diagnosed as having type 3 GM1 gangli osidosis by clinical symptoms and enzyme assay. She was the youngest a mong the patients with type 3 GM1 gangliosidosis whose clinical and ne uroradiological findings have been documented. Clumsiness since early infancy and dystonia since early childhood which progressed slowly wit hout mental deterioration and dysmorphism led us to the diagnosis of t ype 3 GM1 gangliosidosis. Genotype determination showed point mutation in exon 2 of the beta-galactosidase gene, which is common among the p atients reported in Japan. T2-weighted MRI demonstrated bilateral symm etrical hypointensity in the putamen and globus pallidus. Single photo n emission computed tomography using Tc-99m-HMPAO showed bilateral hyp erperfusion in the basal ganglia which decreased gradually during 1 ye ar of observation. Twenty-two patients with type 3 GM1, gangliosidosis reported in the literature whose onset was at under 15 years of age w ere reviewed.