High-altitude long-term hypoxia (LTH) is known to induce pulmonary arterial smooth muscle cell (PASMC) proliferation in the fetus, leading to pulmonary arterial remodeling and pulmonary hypertension of the newborn. The mechanisms underlying these conditions remain enigmatic however. We hypothesized that epigenetic alterations in fetal PASMC induced by high-altitude LTH may play an important rol...

Current methods for definitive prenatal diagnosis of chromosomal aneuploidy, such as chorionic villus sampling and amniocentesis, are invasive and associated with a risk of fetal miscarriage. In 1997, our group reported the presence of fetal DNA in maternal plasma and offered new possibilities for non-invasive prenatal diagnosis. However, fetal DNA exists as a minor fraction among a high backgr...

Epigenetic modifications are heritable changes in gene expression without changes in DNA sequence. DNA methylation has been implicated in the control of several cellular processes including differentiation, gene regulation, development, genomic imprinting and X-chromosome inactivation. Methylated cytosine residues at CpG dinucleotides are commonly associated with gene repression; conversely, st...

Rare nucleated fetal cells circulate within maternal blood. Noninvasive prenatal diagnosis by isolation and genetic analysis of these cells is currently being undertaken. We sought to determine if genetic evidence existed for persistent circulation of fetal cells from prior pregnancies. Venous blood samples were obtained from 32 pregnant women and 8 nonpregnant women who had given birth to male...

OBJECTIVE It was the aim of this study to examine the possible effects of maternal and fetal characteristics on the fetal fraction in maternal plasma cell-free DNA (cfDNA) at 11-13 weeks' gestation. METHODS In a nested case-control study, cfDNA was extracted from maternal plasma obtained before chorionic villous sampling from 300 euploid, 50 trisomy 21 and 50 trisomy 18 pregnancies at 11-13 w...

BACKGROUND Preterm delivery and sub-optimal fetal growth are associated with each other and affect both mother and infant. Our aim was to determine (i) whether there are detectable differences in DNA methylation between early and late gestation and (ii) whether changes in DNA methylation from entry are associated with spontaneous preterm delivery with and without reduced fetal growth. METHODS...

The aim of this study was to establish a link between the highly expressed angiotensin II (Ang II) type 2 receptor (AT2) in human fetal adrenal cells and the proposed apoptotic activity in the center of the gland. There was an important increase in apoptotic DNA fragmentation with age in adrenal glands of fetuses from 15-20 weeks gestation. Adrenal cells showing the characteristic apoptotic int...

National guidelines recommend that all pregnant women be offered screening for fetal chromosomal abnormalities, the majority of which are aneuploidies (an abnormal number of chromosomes). The trisomy syndromes are aneuploidies involving 3 copies of 1 chromosome. Trisomies 21 (T21), 18 (T18), and 13 (T13) are the most common forms of fetal aneuploidy that survive to birth. Noninvasive prenatal s...

The invasive procedures amniocentesis and chorionic villus sampling are routinely applied in pregnancies at risk for fetal genetic disorders and the results obtained are the gold standard for prenatal diagnosis. These procedures have an approximately 0.5-1% risk for fetal loss and are mainly used in cases at risk for fetal chromosomal abnormalities and single-gene disorders. Identification of c...