Clinical and Enzymatic Diagnosis of GMlgangliosidosis; A Case Report

G m1-gangliosidosis is a very rare autosomalrecessive genetic-metabolic disorder,caused by deficiency of the lysosomalenzyme ganglioside-jl-galactosidasethat results in accumulation of glycoseaminoglycans,oligo saccharides, and especially gmlganglioside.herein, we report the clinical and laboratoryfindings of two iranian families with 6 affectedcases. in one of the families, four of the affectedchildren died in the childhood period. all of thedeceased cases were investigated thoroughly beforeand the diagnosis of nieman-pick's diseasewas suggested for them; enzymatic analysis, hadnot been carried out for these cases. in the aliveprobands of the two families, enzyme assaysshowed that the sphingomyelinase activity waswithin normal limits, but ganglioside-pgalactosidaseactivity was deficient in both ofthem. enzyme assays of the patients was carriedout in the metabolic department of the erasmusuniversity based in the rotterdam the netherlands.measurment of the activity of the lysosomic enzyme ganglioside-a-galactosidase showed deficiencyin both of the probands. sphyngomyelinaseand other lysosomal enzyme activity werewithin normal limits.diagnosis in these two families was gmlgangliosidosis.to date these are the only affectedcases confirmed by enzyme assays in iran.