Ultrasound screening of fetuses at increased risk for Down syndrome: how many missed diagnoses?

The ethics of abortions for fetuses with congenital abnormalities

Abortion remains a highly contentious moral issue, with the debate usually framed as a battle between the fetus's right to life and the woman's right to choose. Often overlooked in this debate is the impact of the concurrent legalization of abortion and the development of new prenatal screening tests on the birth prevalence of many inherited diseases. Most proponents of abortion support abortion for fetuses with severe congenital diseases, but there has unfortunately been, in our opinion, too little debate over the moral appropriateness of abortion for much less severe congenital conditions such as Down's syndrome, deafness, and dwarfism. Due to scientific advances, we are looking at a future in which prenatal diagnosis will be safer and more accurate, raising the specter, and the concomitant ethical concerns, of wholesale abortions. Herein, we present a reframing of the abortion debate that better encompasses these conditions and offers a more nuanced position.

The role of perinatal autopsy in the management of pregnancies with major fetal trisomies

We assessed the value of perinatal autopsy following mid-trimester termination of pregnancy due to major fetal trisomies. Singleton fetuses (n=305) that underwent prenatal sonography and karyotyping during the second trimester of pregnancy and that had trisomy 21, trisomy 18, or trisomy 13 constituted the study population. The findings of second trimester sonography and fetal autopsy were compared. Altogether, 611 separate major structural malformations were diagnosed during autopsy. Full agreement was achieved between sonography and autopsy in 35.8% of the malformations. The additional findings at autopsy (64.2%) involved mainly two organ systems: face, including ears and eyes, and extremities, including hands and feet. Some ultrasound findings were not confirmed at autopsy (n=49). Concordance rates between sonography and autopsy findings regarding soft markers were considerably high in cases of increased nuchal fold thickness and short femur/humerus. On the other hand, fetal autopsy was of limited value as far as hyperechoic bowel and echogenic intracardiac foci are concerned. Pathologic examination provides additional information regarding many fetuses with aneuploidy, and may indicate possible directions of sonographic screening for major chromosome aberrations. However, prenatal sonography and perinatal autopsy should be considered as complementary ways of increasing our knowledge about the possible features of fetal aneuploidies.

Proteomic analysis of maternal serum in down syndrome: identification of novel protein biomarkers

Down syndrome (DS) is the most prevalent chromosomal disorder, accounting for significant morbidity and mortality. Definitive diagnosis requires invasive amniocentesis, and current maternal serum-based testing requires a false-positive rate of about 5% to detect 85% of affected pregnancies. We have performed a comprehensive proteomic analysis to identify potential serum biomarkers to detect DS. First- and second-trimester maternal serum samples of DS and gestational age-matched controls were analyzed using multiple, complementary proteomic approaches, including fluorescence 2-dimensional gel electrophoresis (2D-DIGE), 2-dimensional liquid chromatography-chromatofocusing (2D-CF), multidimensional protein identification technology (MudPIT; LC/LC-MS/MS), and MALDI-TOF-MS peptide profiling. In total, 28 and 26 proteins were differentially present in first- and second-trimester samples, respectively. Of these, 19 were specific for the first trimester and 16 for the second trimester, and 10 were differentially present in both trimesters. Analysis of MALDI-TOF-MS peptide profiles with pattern-recognition software also discriminated between DS and controls in both trimesters, with an average recognition capability approaching 96%. A majority of the biomarkers identified are serum glycoproteins that may play a role in cellular differentiation and growth of fetus. Further characterization and quantification of these markers in a larger cohort of subjects may provide the basis for new tests for improved DS screening.