the first step in the prenatal diagnosis of x-linked genetic disorders is determining fetus gender. current invasive methods to obtain the dna source of the fetus instead of its miscarriage risk, has harmful stress for high risk pregnancies. cell free fetal dna (cffdna) circulating in the maternal blood, has now become a useful source of noninvasive prenatal diagnosis. considering limitation of...

Background: It is well documented that fetal DNA can cross the placenta and is present in peripheral maternal blood during pregnancy in human. This fetal DNA also named circulating cell free fetal DNA, has emerged as a valuable source for genetic evaluation. Compared with humans, ovine species have a different structure of placental (synepitheliochorial) with no direct contact between the troph...

BACKGROUND With the advent of massively parallel sequencing (MPS), DNA analysis can now be performed in a genomewide manner. Recent studies have demonstrated the high precision of MPS for quantifying fetal DNA in maternal plasma. In addition, paired-end sequencing can be used to determine the size of each sequenced DNA fragment. We applied MPS in a high-resolution investigation of the clearance...

background: the discovery of circulating fetal dna in maternal blood led to the discovery of new strategies to perform noninvasive testing for prenatal diagnosis. objective: the purpose of the study was to detect fetal aneuploidy at chromosomes 13, 18, 21, x, and y by analysis of fetal cell-free dna from maternal blood, without endangering pregnancy. materials and methods: this retrospective st...

Circulating nucleic acids are present in small amounts in the plasma of healthy individuals. However the discovery of circulating nucleic acids has long been explored for the noninvasive diagnosis of a variety of clinical conditions. The first studies concerning the detection of circulating DNA were investigated for finding various forms of cancer. Metastasis and recurrence in certain tumour ty...

Circulating nucleic acids are present in small amounts in the plasma of healthy individuals. However the discovery of circulating nucleic acids has long been explored for the noninvasive diagnosis of a variety of clinical conditions. The first studies concerning the detection of circulating DNA were investigated for finding various forms of cancer. Metastasis and recurrence in certain tumour ty...

The kinetics and structure of cell-free fetal DNA in maternal plasma is currently under investigation. Plasma fetal DNA seems quite stable albeit cleared rapidly following birth, suggesting continuous fetal DNA release into the maternal circulation during pregnancy. However, to understand better the kinetics of circulating DNA, studies to determine the biological (structural) form in which feta...

variations in detection sensitivity and quantification of fetal DNA concentrations were noted among laboratories very familiar with real-time PCR technology (21). Further studies will be needed to clarify this issue in addition to the continued exploration of other strategies for the investigation of complex fetal genetic traits by analysis of maternal plasma. These strategies may include the e...

BACKGROUND The detection of circulating nucleic acids has long been explored for the non-invasive diagnosis of a variety of clinical conditions. In earlier studies, detection of circulating DNA has been investigated for the detection of various forms of cancer. Metastasis and recurrence in certain cancer types have been associated with the presence of high levels of tumor-derived DNA in the cir...

BACKGROUND The recent discovery of the presence of circulating cell-free fetal DNA in maternal plasma opens up new prenatal diagnostic applications and provides new avenues for clinical investigation. It is of research and potential diagnostic interest to determine whether fetal trisomy 21 may be associated with quantitative abnormalities of circulating fetal DNA in maternal plasma. METHODS M...