Low beta-glucuronidase activity in a healthy member of a family with mucopolysaccharidosis VII.
A phenotypically normal mother of a mucopolysaccharidosis VII child, is reported with an unusually low beta-glucuronidase activity. Low enzyme activity was systemic (6-10% of controls) and residual beta-glucuronidase in leukocytes had an apparently normal Km value. [35S]sulphate incorporation and chase assays in fibroblasts gave values similar to control cells. A normal excretion pattern of glycosaminoglycan was found in this woman's urine. Low enzymatic activity can be related to a non-pathological 'pseudodeficiency' allele for beta-glucuronidase; this woman appears to be an apparent compound heterozygote for this allele and mucopolysaccharidosis VII. Her next pregnancy was monitored by chorionic villus sampling and a heterozygous fetus was suspected. These studies stress the need for complete enzyme investigations of obligate carriers for mucopolysaccharidoses in order to prevent difficulties at prenatal analysis.
Chabas
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Institut de Bioquímica Clínica, Diputació de Barcelona, Spain.
Giros
M L
ML
Guardiola
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D002478:Cells, Cultured; D002675:Child, Preschool; D002824:Chorionic Villi / Q000201:enzymology; D005260:Female; D005347:Fibroblasts / Q000378:metabolism; D005966:Glucuronidase / Q000172:deficiency*; D006025:Glycosaminoglycans / Q000378:metabolism / Q000652:urine; D006579:Heterozygote; D006801:Humans; D008297:Male; D016538:Mucopolysaccharidosis VII / Q000201:enzymology* / Q000235:genetics; D011247:Pregnancy
D006025:Glycosaminoglycans; D005966:Glucuronidase