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Inhibin‐B and pro‐αC‐containing inhibins in amniotic fluid from chromosomally normal and Down syndrome pregnancies
Author(s) -
Wallace Euan M.,
Crossley Jennifer A.,
Riley Simon C.,
Balfour Claire,
Groome Nigel P.,
Aitken David A.
Publication year - 1998
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/(sici)1097-0223(199803)18:3<213::aid-pd242>3.0.co;2-#
Subject(s) - medicine , amniotic fluid , gestation , endocrinology , placenta , pregnancy , down syndrome , fetus , andrology , biology , psychiatry , genetics
In second‐trimester Down syndrome pregnancies, levels of inhibin‐A (the α–β A dimer) in maternal serum and amniotic fluid (AF) are significantly higher and lower than in normal pregnancy, respectively. Since AF also contains inhibin‐B (the α–β B dimer) and precursor inhibins, we have examined whether the secretion of these inhibin isoforms may also be altered in association with Down syndrome. AF from 45 Down syndrome and 150 chromosomally normal pregnancies between 16 and 19 weeks' gestation were analysed, blinded to whether the sample was from a Down syndrome or a normal pregnancy. The median (10th–90th percentiles) inhibin‐B level in the control pregnancies increased from 310·0 (80·8–1112·5) pg/ml at 16 weeks to 459·5 (193·7–1386·8) pg/ml at 19 weeks' gestation. The corresponding figures for precursor inhibins (pro‐αC inhibins) were 541·8 (206·9–1322·8) pg/ml at 16 weeks and 1391·8 (433·3–2652·6) pg/ml at 19 weeks. Expressed as multiples of the median (MOM), the levels of inhibin‐B and pro‐αC inhibins in the Down syndrome samples were 0·85 and 0·79, respectively. Neither was significantly different from the controls. These data suggest that, of the three inhibin subunits, abnormal production or secretion of the inhibin β A ‐subunit may underlie the decreased inhibin‐A levels previously observed in Down syndrome. Confirmation of this by quantitative assessment of the inhibin subunit messenger ribonucleic acids would now be useful. © 1998 John Wiley & Sons, Ltd.