INHIBIN-A AND PRO-ALPHA-C INHIBIN IN DOWN-SYNDROME AND NORMAL PREGNANCIES

Using two enzyme-linked immunosorbent assays specific for inhibin A an d pro-alpha C inhibin, levels of the two proteins were assessed in mat ernal serum from 43 Down syndrome and 300 chromosomally normal pregnan cies at 15-17 weeks' gestation. Compared to the control pregnancies, b oth inhibin A and pro-alpha C inhibin were significantly elevated in t he Down syndrome pregnancies with median levels, expressed as multiple s of the normal median, of 1.53 MoM and 1.34 MoM, respectively (P<0.00 1 and P=0.046 compared to controls). Levels of inhibin A and pro-alpha C inhibin were weakly but significantly correlated in both the contro l and the Down syndrome sera (r=0.25, P<0.0001; r=0.4, P=0.008, respec tively). These data suggest that the mechanism(s) underlying the eleva ted inhibin levels observed in Down syndrome may affect the regulation of both the inhibin alpha- and beta(A)-subunits. (C) 1998 John Wiley & Sons, Ltd.