Amniotic fluid disaccharidases in the prenatal detection of cystic fibrosis.
Intestinal disaccharidases in amniotic fluid were studied in 41 pregnancies with a recurrence risk for cystic fibrosis (CF). In 11 out of 13 pregnancies with CF fetuses the maltase and sucrase activities were either below the control range (8 cases) or below the 10th percentile of control values (3 cases). Trehalase and lactase were slightly less informative indicators of CF. Of the other 28 pregnancies 3 had low amniotic fluid activities of several intestinal enzymes and were terminated, 12 resulted in the birth of a healthy child and 13 are continuing. The findings in fetal CF suggest an impairment of the defaecation of intestinal contents into the amniotic fluid. Reduced or low amniotic fluid disaccharidase activities were also found in other fetal disorders with demonstrated or presumed intestinal anomalies: e.g. anal atresia (2 cases), anencephaly (3 our of the 7 cases), trisomy 13 (5 cases), trisomy 18 (3 of the 5 cases) and trisomy 21 (19 of the 22 cases). Reduced amniotic fluid disaccharidase activities, although not specific for CF, are highly informative in pregnancies at high risk for CF. Using the 10th percentile of the normal range for amniotic fluid disaccharidase activities as an action line, the sensitivity of CF detection is estimated at 80 to 90 per cent, which could in high risk pregnancies reduce the risk of having another affected child from 1 in 4 to 1 in 20.
D000649:Amniocentesis; D000653:Amniotic Fluid / Q000201:enzymology*; D000013:Congenital Abnormalities / Q000201:enzymology; D003550:Cystic Fibrosis / Q000175:diagnosis* / Q000201:enzymology; D003672:Defecation; D004186:Disaccharidases / Q000032:analysis*; D005260:Female; D005315:Fetal Diseases / Q000201:enzymology; D006801:Humans; D007231:Infant, Newborn; D007415:Intestinal Obstruction / Q000201:enzymology; D011247:Pregnancy; D011446:Prospective Studies; D012189:Retrospective Studies; D012306:Risk
D004186:Disaccharidases