title: Amniotic-fluid acetylcholinesterase as a possible diagnostic test for neural-tube defects in early pregnancy.
abstract: Raised levels (greater than or equal to 4.5 munits/ml) of acetylcholinesterase (AChE) activity in amniotic fluid at 14--23 weeks of pregnancy were significantly associated with open fetal neural-tube defects. Out of 72 pregnancies correctly classified by the amniotic-fluid alpha-fetoprotein (A.F.P.) test, 2 of 56 without neural-tube defects and all 16 with open neural-tube defects (8 with anencephaly and 8awith open spina bifida) had raised levels of AChE. Out of 5 pregnancies misclassified by the A.F.P. test (4 without neural-tube defects and 1 with open spina bifida), only 1 was misclassified by the AChE test--namely, one of those without a neural-tube defect. Thus, only 3 of the 77 pregnancies tested were misclassified by the quantitative AChE test. A qualitative test for an isoenzyme of AChE found in cerebrospinal fluid correctly classified these 3 pregnancies. These findings suggest that the analysis of AChE in amniotic fluid may be a useful test in the diagnosis of open neural-tube defects.
mesh_terms: D000110:Acetylcholinesterase / Q000032:analysis*; D000653:Amniotic Fluid / Q000032:analysis / Q000201:enzymology*; D000757:Anencephaly / Q000175:diagnosis / Q000201:enzymology; D004796:Clinical Enzyme Tests; D004591:Electrophoresis, Polyacrylamide Gel; D005069:Evaluation Studies as Topic; D005188:False Negative Reactions; D005189:False Positive Reactions; D005260:Female; D006801:Humans; D009436:Neural Tube Defects / Q000175:diagnosis*; D011247:Pregnancy; D011261:Pregnancy Trimester, First; D011262:Pregnancy Trimester, Second; D011296:Prenatal Diagnosis; D016136:Spina Bifida Occulta / Q000175:diagnosis / Q000201:enzymology; D000509:alpha-Fetoproteins / Q000032:analysis
chemical_list: D000509:alpha-Fetoproteins; D000110:Acetylcholinesterase