PRENATAL-DIAGNOSIS OF THE CARBOHYDRATE-DEFICIENT GLYCOPROTEIN SYNDROME TYPE 1A (CDG1A) BY A COMBINATION OF ENZYMOLOGY AND GENETIC-LINKAGE ANALYSIS AFTER AMNIOCENTESIS OR CHORIONIC VILLUS SAMPLING
J. Charlwood et al., PRENATAL-DIAGNOSIS OF THE CARBOHYDRATE-DEFICIENT GLYCOPROTEIN SYNDROME TYPE 1A (CDG1A) BY A COMBINATION OF ENZYMOLOGY AND GENETIC-LINKAGE ANALYSIS AFTER AMNIOCENTESIS OR CHORIONIC VILLUS SAMPLING, Prenatal diagnosis, 18(7), 1998, pp. 693-699
Two pregnancies at risk for the carbohydrate-deficient glycoprotein sy
ndrome Type 1A (CDG1A: phosphomannomutase deficient) were monitored by
enzyme and genetic linkage analyses. The index case in both families
had a proven deficiency of phosphomannomutase (PMM). An unaffected fet
us was predicted in family 1 following amniocentesis. Normal PMM activ
ity was found in cultured amniotic fluid cells and there was no elevat
ion of lysosomal enzymes in the amniotic fluid. Genetic linkage analys
is using microsatellite markers closely linked to the CDG1A gene confi
rmed this prediction. A healthy child was born. In the second family d
irect assay of chorionic villi showed a profound deficiency of PMM and
genetic linkage analysis showed the fetus to have the same haplotype
as the proband. The pregnancy was terminated and a deficiency of PMM w
as confirmed in cultured fibroblasts from the fetus. Reliable prenatal
diagnosis of CDG Type 1A (PMM-deficient) can be achieved by a combina
tion of biochemical and molecular genetic tests. (C) 1998 John Wiley &
Sons, Ltd.