beta-Glucuronidase deficiency: identification of an affected fetus with simultaneous sampling of chorionic villus and amniotic fluid.

Four pregnancies at risk for mucopolysaccharidosis VII were monitored by chorionic villus sampling obtained in the first or second trimester of gestation. One fetus showed reduced beta-glucuronidase activity following simultaneous sampling of chorionic villus and amniotic fluid at 17 weeks of gestation. The pregnancy was terminated. Subsequent assay of beta-glucuronidase activity in the fetal tissues was consistent with a diagnosis of mucopolysaccharidosis VII, thus confirming that chorionic villus samples provide useful information for diagnosis of this condition.