Low beta-glucuronidase activity in a healthy member of a family with mucopolysaccharidosis VII

J Inherit Metab Dis. 1991;14(6):908-14. doi: 10.1007/BF01800472.


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.

Publication types

  • Case Reports
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Cells, Cultured
  • Child, Preschool
  • Chorionic Villi / enzymology
  • Female
  • Fibroblasts / metabolism
  • Glucuronidase / deficiency*
  • Glycosaminoglycans / metabolism
  • Glycosaminoglycans / urine
  • Heterozygote
  • Humans
  • Male
  • Mucopolysaccharidosis VII / enzymology*
  • Mucopolysaccharidosis VII / genetics
  • Pregnancy


  • Glycosaminoglycans
  • Glucuronidase