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Amniotic fluid enzymes in pregnancies with trisomy 21
Author(s) -
Giddy M. J.,
Hay D. L.,
Horacek I.
Publication year - 1989
Publication title -
prenatal diagnosis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.956
H-Index - 97
eISSN - 1097-0223
pISSN - 0197-3851
DOI - 10.1002/pd.1970091105
Subject(s) - amniotic fluid , amniocentesis , trisomy , alpha fetoprotein , medicine , aneuploidy , prenatal diagnosis , andrology , pregnancy , gastroenterology , biology , fetus , biochemistry , genetics , chromosome , hepatocellular carcinoma , gene
The activities of a range of microvillous enzymes in amniotic fluid from normal pregnancies ( n = 213) and those complicated by trisomy 21 ( n = 26) were compared in a prospective study. Using a centrifugal analyser, the activities of leucine aminopeptidase (LAP), gamma glutamyl transferase (GGT), aspartate transferase (AST), and isoenzymes of alkaline phosphate (ALP) were measured in amniotic fluid alongside alpha fetoprotein (AFP) levels. Of the markers studied, LAP was found to be the most reliable indicator of trisomy 21. Using levels below the 5th percentile, LAP showed sensitivity 73 per cent, specificity 94 per cent, and predictive value positive 63 percent. Although these tests would not replace karyotyping in all cases, the measurement of LAP could be useful as a rapid initial screening test, particularly when amniocentesis is performed for indications other than chromosomal abnormalities.