Screening for trisomy 21 in twin pregnancies poses a serious clinical, ethical and moral dilemma (Reynolds, 1995), leading some authors to advocate that such screening should be discouraged (Wald et al., 1997). Nevertheless, algorithms have been developed (Wald et al., 1991; Spencer et al., 1994) for biochemical screening in twins during the second trimester which will allow detection of approx...

In a study of 2923 normal pregnancies and 203 pregnancies affected by trisomy 21 we have shown a significant difference in the median MoM of the markers: fetal nuchal translucency, maternal serum free beta-hCG and PAPP-A in the presence of a female fetus compared with a male fetus. For maternal serum free beta-hCG levels are higher by 15% if the fetus is chromosomally normal and by 11% if the f...

down syndrome (ds) is a birth defect with huge medical and social costs, caused by trisomy of whole or part of chromosome 21. it is the most prevalent genetic disease worldwide and the common genetic cause of intellectual disabilities appearing in about 1 in 400-1500 newborns. although the syndrome had been described thousands of years before, it was named after john langdon down who described ...

OBJECTIVE To determine the likelihood ratio for trisomy 21 in fetuses with tricuspid regurgitation at the 11 to 13 + 6-week scan. METHODS Fetal echocardiography was carried out by specialist pediatric cardiologists in 742 singleton pregnancies at 11 to 13 + 6 weeks' gestation and pulsed wave Doppler was used to ascertain the presence or absence of tricuspid regurgitation. To avoid confusion w...

Cytogenetic studies were performed on 150 cases of Down's syndrome (DS) in Iran. The standard trisomy 21 was found in 132 (88 % ) and translocation-trisomy 21 (+21) in 18 (12%) patients, i.e., t(21,21) in 1(0.63%) and mosaicism in 17(11.33%) cases. The comparison of the frequencies for mosaicism between different populations such as Denmark, Hungary, Egypt, Iraq, India, Australia and Iran ...

OBJECTIVE To evaluate the prefrontal space ratio (PFSR) in second- and third-trimester euploid fetuses and fetuses with trisomy 21. METHODS This was a retrospective study utilizing stored mid-sagittal two-dimensional images of second- and third-trimester fetal faces that were recorded during prenatal ultrasound examinations at the Department of Prenatal Medicine at the University of Tuebingen...

OBJECTIVE To determine the possible association between single umbilical artery (SUA) at 11-14 weeks of gestation and the incidence of chromosomal abnormalities. METHODS Color flow imaging of the fetal pelvis was used to determine the number of umbilical arteries in 717 fetuses immediately before chorionic villus sampling for karyotyping at 11-14 weeks' gestation. RESULTS Single umbilical a...

OBJECTIVE To compare the maternal serum concentration of placental growth factor-1 (PlGF-1) and PlGF-2 at 11-13 weeks' gestation in normal pregnancies and in those complicated by preeclampsia (PE), delivery of small for gestational age (SGA) neonates and fetal trisomies 21, 18 and 13. METHODS Serum PlGF-1 and PlGF-2 were measured in 270 pathological pregnancies (PE, n = 80; SGA, n = 80; triso...

Our objective was to determine if whole genome amplification (WGA) provides suitable DNA for qPCR-based genotyping for human embryos. Single blastomeres (Day 3) or trophoblastic cells (Day 5) were isolated from 342 embryos for WGA. Comparative Genomic Hybridization determined embryo sex as well as Trisomy 18 or Trisomy 21. To determine the embryo's sex, qPCR melting curve analysis for SRY and D...

A chromosomal disorder caused by the presence of all or part of an extra 21st chromosome is known as the Down syndrome, or trisomy 21, or trisomy G. In the last fifteen years it has become possible to observe these features by ultrasound examination in the third month of intrauterine life. About 75% of trisomy 21 fetuses have absent nasal bone. In the present work, neural network schemes that h...