Turner Syndrome and Multiple-Marker Screening

Abstract

The measurement of maternal serum concentrations of α-fetoprotein (AFP), human chorionic gonadotropin (hCG), and unconjugated estriol (uE3) in conjunction with maternal age has been used as a prenatal screen for Down syndrome and trisomy 18 (1)(2)(3). Several reports have found that pregnancies associated with Turner syndrome may also be identified as a result of an increased risk for Down syndrome (4)(5)(6)(7). The AFP/hCG/uE3 screening program at the Wake Forest University School of Medicine screens ∼15 000 maternal serum samples per year. Results from all samples screened between January 1989 and December 1997 and their respective outcomes were reviewed. In this study we report the maternal serum AFP concentrations in 19 pregnancies, the total hCG in 17 pregnancies, and the uE3 in 7 pregnancies identified with fetal Turner syndrome. In addition, these results are correlated with the ultrasound findings of cystic hygroma and hydrops. Results from 130 595 maternal serum samples assayed between January 1989 and December 1997 and their respective outcomes were reviewed. Maternal serum screening was performed between 15.0 and 20.9 weeks of gestation. An assay for total hCG was added to the screen in January 1991, and uE3 was added in November 1993. AFP and total hCG were measured by the Abbott IMx microparticle enzyme immunoassay system; uE3 was assayed with a radioimmunoassay by Diagnostic Systems Laboratories according to the manufacturer’s instructions. Maternal serum AFP values were corrected for gestational age, maternal weight, race, and insulin-dependent diabetic status. Maternal serum hCG and uE3 values were corrected for gestational age and maternal weight. A patient-specific Down syndrome risk was calculated using maternal age and a trivariate gaussian distribution (8). All median values were calculated in house. Samples were identified as having an …