Second trimester levels of maternal serum total activin A and placental inhibin/activin alpha and betaA subunit messenger ribonucleic acids in Down syndrome pregnancy.
OBJECTIVE
Previous data have shown that inhibin A (alpha/betaA) is increased about twofold in maternal serum samples from Down syndrome pregnancy. Our objectives were to determine whether activin A (betaA/betaA) was similarly increased in maternal serum from pregnancies affected with fetal Down syndrome, and to investigate whether increased expression of each inhibin/activin subunit occurred in placental tissue from cases of fetal Down syndrome.


METHODS
Maternal serum total activin A levels were measured in 20 cases of fetal Down syndrome and 100 unaffected pregnancy samples. In addition, analysis of inhibin/activin alpha and betaA subunit mRNA levels was performed in placental tissue extracts from six cases of fetal Down syndrome and six tissues with a normal karyotype.


RESULTS
The median total activin A level in the Down syndrome cases was 0.82 MoM (multiples of the median); values did not differ significantly (P = 0.36, Mann-Whitney U analysis) from those in unaffected pregnancies. The inhibin alpha subunit/GAPDH mRNA ratio, but not that of betaA subunit/GAPDH mRNA, was significantly greater (P < 0.01, ANOVA) in placental tissue from Down syndrome than in control placental tissue.


CONCLUSIONS
Unlike inhibin A, activin A is not significantly increased in Down syndrome relative to unaffected pregnancy. Furthermore, increased amounts of maternal serum inhibin A in Down syndrome pregnancy probably result from increased placental expression of inhibin alpha, but not betaA, subunit.
Lambert-Messerlian
G M
GM
Department of Pathology and Laboratory Medicine, Brown University School of Medicine, Women and Infants Hospital, Providence, Rhode Island 02905, USA.
Luisi
S
S
Florio
P
P
Mazza
V
V
Canick
J A
JA
Petraglia
F
F
D028341:Activins; D004314:Down Syndrome / Q000097:blood*; D005260:Female; D005865:Gestational Age; D006801:Humans; D007265:Inhibins / Q000097:blood*; D010446:Peptide Fragments / Q000097:blood* / Q000235:genetics; D010920:Placenta / Q000378:metabolism; D011247:Pregnancy; D011248:Pregnancy Complications / Q000097:blood; D011257:Pregnancy Proteins / Q000097:blood*; D011262:Pregnancy Trimester, Second; D012333:RNA, Messenger / Q000097:blood*
D010446:Peptide Fragments; D011257:Pregnancy Proteins; D012333:RNA, Messenger; D028341:Activins; D007265:Inhibins