Predictive value of the triple screening test for the phenotype of Down syndrome

Maternal serum alpha-fetoprotein (MS-AFP), human chorionic gonadotropin (hC G), and unconjugated estriol (uE3) are routinely measured in the second tri mester ("triple" test) and combined with maternal age to evaluate risk for fetal Down syndrome. Triple test results and clinical findings were retrosp ectively reviewed for 30 newborns with Down syndrome to determine whether a nalyte values or second trimester risks for Down syndrome were more extreme in affected pregnancies where cardiac or other severe congenital malformat ions were present compared to those cases where major anatomical abnormalit ies were absent. Mean MS-AFP, uE3, maternal age, and second trimester Down syndrome risk were all similar in the two groups of pregnancies. However, h CG; concentrations did appear to be higher in the group of Down syndrome pr egnancies with anatomical anomalies (mean 1.74 MoM versus 1.19 MoM) (P < 0. 05), Overall, there was no significant difference in the incidence of major anom alies in patients with screen-positive test results versus those cases that were not identified by the triple test, Prenatal counseling should therefo re reflect the general expectations of the Down syndrome phenotype that hav e been established from live-born infants with this disorder. Am. J. Med. G enet, 85:123-126, 1999, (C) 1999 Wiley-Liss, Inc.