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Fetal DNA (fetal + dna)
Kinds of Fetal DNA Selected AbstractsFetal gender determination in early first trimester pregnancies of rhesus monkeys (Macaca mulatta) by fluorescent PCR analysis of maternal serumJOURNAL OF MEDICAL PRIMATOLOGY, Issue 6 2003Daniel F. Jimenez Abstract:, Non-human primate fetal gender determination can be a powerful tool for research study design and colony management purposes. The recent discovery of the presence of fetal DNA in maternal serum has offered a new non-invasive approach for identification of fetal gender. We present a rapid and simple method for the sexing of developing rhesus monkeys in the first trimester by polymerase chain reaction (PCR) analysis of maternal serum. Serum samples were obtained from 72 gravid rhesus monkeys during 20,32 days of gestation (term 165 ± 10 days). Fetal gender and the quantity of circulating fetal DNA were determined by real-time PCR analysis of the rhesus Y-chromosomal DNA sequences. The sensitivity for identifying a male fetus was 100% by 30 days gestation, and no false-positive results were observed. This study demonstrates that fetal gender can be reliably determined in the early first trimester from maternal serum samples, a non-invasive method for routine gender screening. [source] Recent advances in non-invasive prenatal DNA diagnosis through analysis of maternal bloodJOURNAL OF OBSTETRICS AND GYNAECOLOGY RESEARCH (ELECTRONIC), Issue 6 2007Akihiko Sekizawa Abstract Prenatal diagnosis of aneuploidy and single-gene disorders is usually performed by collecting fetal samples through amniocentesis or chorionic villus sampling. However, these invasive procedures are associated with some degree of risk to the fetus and/or mother. Therefore, in recent years, considerable effort has been made to develop non-invasive prenatal diagnostic procedures. One potential non-invasive approach involves analysis of cell-free fetal DNA in maternal plasma or serum. Another approach utilizes fetal cells within the maternal circulation as a source of fetal DNA. At the present time, fetal gender and fetal RhD blood type within RhD-negative pregnant women can be reliably determined through analysis of maternal plasma. Furthermore, genetic alterations can be diagnosed in the maternal plasma when the mother does not have the alterations. However, the diagnosis of maternally inherited genetic disease and aneuploidy is limited using this approach. Non-invasive prenatal diagnosis through examination of intact fetal cells circulating within maternal blood can be used to diagnose a full range of genetic disorders. Since only a limited number of fetal cells circulate within maternal blood, procedures to enrich the cells and enable single cell analysis with high sensitivity are required. Recently, separation methods, including a lectin-based method and autoimage analyzing, have been developed, which have improved the sensitivity of genetic analysis. This progress has supported the possibility of non-invasive prenatal diagnosis of genetic disorders. In the present article, we discuss recent advances in the field of non-invasive prenatal diagnosis. [source] Noninvasive Prenatal Diagnosis: Past, Present, and FutureMOUNT SINAI JOURNAL OF MEDICINE: A JOURNAL OF PERSONALIZED AND TRANSLATIONAL MEDICINE, Issue 6 2009Christian Litton MD Abstract The presence of fetal cells in the maternal circulation was first noted by Georg Schmorl when he documented the presence of multinucleated syncytial giant cells of placental origin in the lung tissue of women who had died from complications of eclampsia. In the intervening century, advances in cellular and molecular biology further elucidated both the physiology and pathophysiology of communication within the fetomaternal unit. This concept is at the foundation of the rapidly expanding field of noninvasive prenatal diagnosis. However, the clinical utility of this phenomenon had been limited until the presence of cell-free fetal DNA circulating in the maternal plasma was reported in 1997 and fetal messenger RNA was demonstrated to circulate in the maternal plasma in 2000. These circulating nucleic acids are found free-floating in the maternal plasma, unencumbered by a surrounding fetal cell. The analysis of these 3 fetal markers (fetal cells, cell-free fetal DNA, and fetal messenger RNA) for diagnostic and screening purposes is now being developed. The scope of noninvasive prenatal diagnosis is not limited to only the diagnosis of fetal genetic traits and aneuploidies. Recently, researchers have focused their investigations on the role of cell-free fetal DNA and fetal messenger RNA in preeclampsia, intrauterine growth restriction, and preterm labor. These biomarkers, the result of inherent placental dysfunction or the byproducts of placental trophoblastic apoptosis, may allow for improvements in the diagnosis and management of high-risk pregnancies. Mt Sinai J Med 76:521-528, 2009. © 2009 Mount Sinai School of Medicine [source] Fetal sex determination using circulating cell-free fetal DNA (ccffDNA) at 11 to 13 weeks of gestationPRENATAL DIAGNOSIS, Issue 10 2010Ranjit Akolekar Abstract Objective To examine the performance of a mass spectrometry-based detection platform using three Y-chromosome sequences for fetal sex determination from circulating cell-free fetal DNA (ccffDNA) in maternal blood in the first trimester of pregnancy. Methods We extracted ccffDNA for the determination of fetal sex from stored maternal plasma obtained at 11 to 13 weeks' gestation from singleton pregnancies with documented fetal gender. Mass spectrometry was used to examine 236 specimens for the presence of three Y-chromosome sequences (SRY, DBY and TTTY2). The sample was classified as male, female or inconclusive depending on the detection of three, one/none and two sequences, respectively. Results Three (1.3%) of the 236 cases were classified as invalid due to the absence of a well-defined spectral peak for TGIF and 22 (9.3%) were reported as inconclusive. In the 211 cases with a valid result, the fetal sex was correctly identified in 90 of 91 male babies and 119 of 120 female babies giving an accuracy of 99.1% and sensitivity and specificity for prediction of male fetuses of 98.9 and 99.2%, respectively. Conclusion Fetal sex determination can be accurately determined from maternal ccffDNA in the first trimester of pregnancy using mass spectrometry analysis. Copyright © 2010 John Wiley & Sons, Ltd. [source] Management of red cell alloimmunisation in pregnancy: the non-invasive monitoring of the diseasePRENATAL DIAGNOSIS, Issue 7 2010Sebastian Illanes Abstract Haemolytic disease of the fetus and newborn (HDFN) due to red cell alloimmunization was a significant cause of fetal and neonatal morbidity and mortality until the introduction of anti-D immunoglobulin, which has dramatically changed the incidence of the disease. However, it is still a major problem in affected pregnancies. The emphasis of current clinical management has shifted from an invasive approach to non-invasive monitoring of the disease. The key elements of the modern management are determining which fetuses are at risk of HDFN with the use of cell-free fetal DNA in maternal plasma (fetal RHD genotype) and the follow-up of antigen positive fetuses by Doppler ultrasonography to detect anaemia severe enough to need treatment. When anaemia is suspected, an invasive approach is still required in a timely manner for confirmation of the degree of anaemia and to administer blood transfusions. This non-invasive approach prevents unnecessary administration of human-derived blood products, with the consequent ethical and cost implications and most importantly avoids iatrogenic conversion of mild to severe disease by avoiding need for techniques such as amniocentesis. The potential problem of the non-invasive approach is the reduction in the total number of invasive procedures, with the subsequent difficulty of maintaining the skills required to perform them. Copyright © 2010 John Wiley & Sons, Ltd. [source] Noninvasive prenatal diagnosis of fetal blood group phenotypes: current practice and future prospectsPRENATAL DIAGNOSIS, Issue 2 2009Geoff Daniels Abstract Fetuses of women with alloantibodies to RhD (D) are at risk from hemolytic disease of the fetus and newborn, but only if the fetal red cells are D-positive. In such pregnancies, it is beneficial to determine fetal D type, as this will affect the management of the pregnancy. It is possible to predict, with a high level of accuracy, fetal blood group phenotypes from genotyping tests on fetal DNA. The best source is the small quantity of fetal DNA in the blood of pregnant women, as this avoids the requirement for invasive procedures of amniocentesis or chorionic villus sampling (CVS). Many laboratories worldwide now provide noninvasive fetal D genotyping as a routine service for alloimmunized women, and some also test for c, E, C and K. In many countries, anti-D immunoglobulin injections are offered to D-negative pregnant women, to reduce the chances of prenatal immunization, even though up to 40% of these women will have a D-negative fetus. High-throughput, noninvasive fetal D genotyping technologies are being developed so that unnecessary treatment of pregnant women can be avoided. Trials suggest that fetal D typing of all D-negative pregnant women is feasible and should become common practice in the near future. Copyright © 2008 John Wiley & Sons, Ltd. [source] Prenatal diagnosis of oculocutaneous albinism type II and novel mutations in two Chinese familiesPRENATAL DIAGNOSIS, Issue 6 2007Li Hongyi Abstract Objective The prenatal genetic diagnosis and counseling of oculocutaneous albinism type II (OCA2) by detecting mutations in the OCA2 gene Methods DNA samples were extracted from peripheral whole blood and amniocentesis-derived cells. Polymerase chain reaction and automatic sequence analysis were used to screen the OCA2 gene. Results Case 1: Two novel heterozygous mutations (p.N476D and p.Y827H) in the P gene were detected in the proband. Molecular prenatal diagnosis on fetal DNA revealed N476D. The pregnancy progressed uneventfully to a normal outcome. Case 2: Mutation analysis of the DNA of family 2 revealed compound heterozygosities for two novel P gene mutations (p.N476D and p.G775R). The pregnant female and the fetus each presented with a single P gene mutation (p.V443I and G775R, respectively). The pregnancy was continued. Conclusion This is the first report of prenatal diagnosis performed in families with oculocutaneous albinism type II (OCA2). Also, this report reveals three novel mutations of the P gene. Copyright © 2007 John Wiley & Sons, Ltd. [source] Free fetal DNA in maternal circulation: a potential prognostic marker for chromosomal abnormalities?PRENATAL DIAGNOSIS, Issue 2 2007Ageliki Gerovassili Abstract Objectives Previous studies on the association of fetal cell-free (cf)DNA levels in maternal circulation have produced conflicting results but the sample sizes were small and based on archived material. We aimed to quantify the levels of fetal and total cfDNA on prospectively collected samples, to understand their correlation with other variables and to clarify their diagnostic value. Methods DNA from pre-CVS maternal plasma was extracted from 264 controls, 72 trisomy 21, 24 trisomy 18, 12 trisomy 13, 16 Turner's syndrome and 8 triploidy first-trimester pregnancies and quantified using real-time PCR. ,-globin was used to determine total cfDNA levels and DYS14 and SRY assays to determine fetal cfDNA levels. Results Fetal cfDNA levels (DYS14) showed correlation with crown rump length (CRL) (p = 0.004), BMI (p = 0.01) and storage time (p = 0.007) while there was an inverse correlation of total cfDNA levels with nuchal translucency (NT) (p = 0.001). No significant difference was observed between the levels of fetal cfDNA in controls and aneuploidy cases. Conclusion Quantification of fetal and total cfDNA in maternal circulation showed inverse correlation between NT and total cfDNA levels. Our results also suggest that fetal cfDNA is not an ideal prognostic marker for chromosomal abnormalities in first-trimester pregnancies. Copyright © 2006 John Wiley & Sons, Ltd. [source] Improvement in fetal DNA extraction from maternal plasma.PRENATAL DIAGNOSIS, Issue 1 2007Evaluation of the NucliSens Magnetic Extraction system, the QIAamp DSP Virus Kit in comparison with the QIAamp DNA Blood Mini Kit Abstract Objective Prenatal diagnostic assays have been developed using free fetal DNA circulating in the maternal blood of pregnant women. Efficient DNA extraction is crucial for a robust analysis. To improve fetal DNA yield, we tested two manual extraction methods,the NucliSens Magnetic Extraction (NMAG) system and the QIAamp DSP Virus Kit (QDSP),against our current standard method, the widely used QIAamp DNA Blood Mini Kit (QDNA). Methods The fetal DNA yield of the two extraction systems was evaluated using the RHD exon 7 as target in DNA extracts of 75 plasma samples from pregnant RhD-negative women, known to have given birth to RhD-positive infanto. The total DNA yield was evaluated in 23 samples, targeting GAPDH. Results The fetal DNA yield was improved by a mean factor of 1.7 using the NMAG system, and improved by a mean factor of 1.5 using the QDSP. The total DNA yield was improved by a mean factor of 2.3 using the NMAG system, and by a mean factor of 1.3 using the QDSP. Conclusion Both extraction systems tested were superior to our standard with regard to DNA yield. This improvement may have a great impact on the success of genotyping in early pregnancy. Copyright © 2007 John Wiley & Sons, Ltd. [source] Comparison of activin A and cell-free fetal DNA levels in maternal plasma from patients at high risk for preeclampsiaPRENATAL DIAGNOSIS, Issue 13 2006Claude Henri Diesch Abstract Objectives We examined the concentration of activin A in a prospective manner before the clinical manifestation of preeclampsia and compared the data with those of cell-free fetal DNA in the maternal plasma. Methods The levels of activin A were analysed by enzyme-linked immunosorbent assay (ELISA) for pregnant women: (1) with preeclampsia (n = 34) in the third-trimester and normal controls (n = 44); and (2) at-risk of preeclampsia in the second-trimester (n = 15) as indicated by uterine artery Doppler and normal controls (n = 68). Correlation between activin A level and cell-free fetal DNA level was examined using the Spearman rank test. Results The level of plasma activin A was significantly higher in the preeclamptic samples (12.056 vs 7.068 ng/mL, p = 0.000). The increase in the activin A concentration was observed prior to the onset of preeclampsia (3.483 vs 1.324 ng/mL, p = 0.000). This increase in activin A correlated significantly with the increased level of cell-free fetal DNA, in the maternal circulation prior to the onset of preeclampsia (r = 0.977, p = 0.000). Conclusion Our data suggest that circulatory activin A could be an independent biomarker for the early identification and monitoring of preeclampsia. Copyright © 2006 John Wiley & Sons, Ltd. [source] Non-invasive diagnosis of fetal sex; utilisation of free fetal DNA in maternal plasma and ultrasoundPRENATAL DIAGNOSIS, Issue 7 2006Neil D. Avent Abstract Non-invasive prenatal diagnosis is now a clinical reality, using both early ultrasound and molecular DNA methods. Technical advances in the sensitivity of the polymerase chain reaction (PCR), coupled with the finding that significant levels of fetal DNA (ffDNA) are found in maternal plasma and serum, has enabled the ready detection of paternally inherited genes or polymorphisms. Routine maternal plasma-based genotyping is now available for the determination of fetal sex and RHD blood group status (Van der Schoot et al., 2003). This review touches briefly on the ultrasound diagnoses and then focuses on the application of free ffDNA for fetal sex determination, indicating the Y-chromosome targets exploited in this strategy and the merits of their utilisation. Copyright © 2006 John Wiley & Sons, Ltd. [source] Reduction in diagnostic and therapeutic interventions by non-invasive determination of fetal sex in early pregnancyPRENATAL DIAGNOSIS, Issue 12 2005Jon A. Hyett Abstract Objective This study reviews our clinical experience of non-invasive techniques for early sex determination. It assesses the effectiveness of these techniques at reducing invasive prenatal testing for X-linked genetic disease or for ambiguous development of the external genitalia. Methods A prospective cohort study of 30 pregnancies was referred to a tertiary unit for prenatal diagnosis. Fetal gender was determined using two non-invasive techniques: analysis of free fetal DNA (ffDNA) in maternal plasma and ultrasound visualisation. The results were compared to fetal gender determined by invasive testing or at birth. Results Fetal gender was accurately determined by analysis of ffDNA at a mean of 10 + 1 (7 + 6 to 14 + 1) weeks' gestation in all cases. Ultrasound assessment was accurate in 20 of the 23 cases where this was attempted at 12 + 0 (10 + 4 to 14 + 1) weeks' gestation, but could not be determined in the remaining 3 cases. Thirteen of 28 (46%) women chose not to have invasive testing on the basis of these findings. Conclusions Both the techniques appear to offer an accurate means of assessing fetal gender, giving parents the option of avoiding invasive testing in the 50% of cases where the fetus would not be affected. The molecular technique is performed at an earlier gestation, but female fetal status is predicted by a negative test result. Ultrasound cannot be applied until 11 weeks' gestation but diagnostic signs are sought in both sexes. Combining these approaches offers a highly sensitive method of non-invasive determination of gender in high-risk pregnancies. Health professionals, clinical geneticists and genetics associates, in particular, who refer women at high risk should be aware of these non-invasive options for prenatal sex determination. Copyright © 2005 John Wiley & Sons, Ltd. [source] Cell-free fetal DNA (SRY locus) concentration in maternal plasma is directly correlated to the time elapsed from the onset of preeclampsia to the collection of bloodPRENATAL DIAGNOSIS, Issue 4 2004Antonio Farina MD Abstract Objective To determine (1) if fetal DNA (fDNA) in the maternal circulation in women affected by preeclampsia correlates with the time elapsed from the onset of symptoms to the time of blood collection, and (2) if the inclusion of this variable improves the discrimination between affected and unaffected patients by using fDNA distributions. Methods Plasma were collected from 34 women at 33.7 ± 3.9 weeks' gestation, affected by preeclampsia, and bearing a single male fetus. fDNA was extracted from 1.5-mL plasma samples, and the SRY and ,-globin gene were analyzed by real-time quantitative PCR. MoMs (multiple of the control median) were calculated by using a log equation of 102 normal cases. Log MoMs were then plotted against the time elapsed from onset of symptoms to blood collection (expressed in days) by means of a log-linear regression. Adjusted MoMs were then calculated. ROC curves were used to test the discrimination obtained by using adjusted MoMs. Results The median MoMs of controls and preeclamptic patients were 1.00 ± 1.53 and 2.62 ± 2.70 respectively. By plotting log MoM fDNA against the time elapsed from onset of symptoms to blood collection, we found a significant positive correlation, (p -value < 0.001, R2 = 0.55, F = 38.97, from 1 to 50 days). The adjusted median fDNA MoM was 2.66 ± 2.50. Areas under the curves, as estimated by ROC curves, were 76.7 for unadjusted and 85.5 for adjusted MoMs respectively (p -value = 0.02). Conclusions The effect of a further covariate showed that (1) fDNA passage from trophoblasts to maternal circulation for unit of time is proportional to the duration of the damage and that (2) increased discrimination can be obtained in comparison to normal subjects. Copyright © 2004 John Wiley & Sons, Ltd. [source] Earliest gestational age for fetal sexing in cell-free maternal plasmaPRENATAL DIAGNOSIS, Issue 13 2003R. J. P. Rijnders Abstract Objectives To evaluate at what gestational age fetal DNA can reliably be detected at the earliest in maternal plasma. Methods We performed consecutive blood sampling in the first trimester of pregnancy in 17 women who were pregnant after in vitro fertilization (IVF) or intrauterine insemination (IUI). DNA was isolated and the Y-chromosome specific SRY was amplified by real-time polymerase chain reaction (PCR). We likewise studied 31 women prior to invasive prenatal diagnosis procedures for test validation purposes. All test results were compared to cytogenetic sex or sex at birth. Results The earliest SRY detection was at a gestational age of 5 weeks and 2 days. In none of 4 pregnancies ending in a miscarriage was SRY detected. We detected SRY in maternal plasma in 1 of 2 patients (50%) carrying a male fetus at a gestational age of 5 weeks, in 4 of 5 (80%) at a gestational age of 7 weeks, in 4 of 4 (100%) at a gestational age of 9 weeks. In all 7 women pregnant with a male fetus, the correct fetal sex was detected by 10 weeks. In none of the 6 patients who delivered a girl was SRY detected. In the validation group, SRY was detected in 13 of the 13 male, and none of the 18 female fetuses. Conclusions We conclude that real-time PCR of the SRY gene promises to be a reliable technique for early fetal sexing in maternal plasma. Copyright © 2003 John Wiley & Sons, Ltd. [source] Cell-free fetal DNA concentration in plasma of patients with abnormal uterine artery Doppler waveform and intrauterine growth restriction,a pilot studyPRENATAL DIAGNOSIS, Issue 5 2003Elisabetta Caramelli Abstract Objective To evaluate if an increased amount of fetal DNA concentration can be found in women screened positive for intrauterine growth restriction because of abnormal uterine artery Doppler waveforms. Methods We enrolled eight pregnant women (each bearing a male fetus), with the evidence of abnormal uterine artery Doppler waveforms, and 16 control patients for a case-control study matched for gestational age (1 : 2). Uterine artery Doppler was carried out at 20 to 35 weeks' gestation (median 29). The mean uterine artery resistance index (RI) was subsequently calculated, and a value >0.6 was considered positive for the clinical features of pre-eclampsia. The SRY locus was used to determine the amount of male fetal DNA in the maternal plasma at the time of Doppler analysis. Results Two controls (normal Doppler) were excluded from the final analysis because they had a pre-term delivery. One case (abnormal Doppler) had evidence of intrauterine growth restriction at the time of enrolment. In four out of eight cases (abnormal Doppler), intrauterine growth restriction was subsequently observed. Multiples of median (MoM) conversion of the fetal DNA values showed an increase of 1.81 times in the cases when compared to the controls. An increase of 2.16 times was instead observed for the cases with a growth-restricted fetus (5 cases out of 8) in comparison with the controls (14 cases). Conclusions In subjects positive to uterine artery Doppler velocimetry analysis (Doppler analysis for pre-eclampsia screening), the fetal DNA concentration is higher than expected, in the absence of any other clinical feature. Since the increase in fetal DNA seems to be related to the presence or to the future development of intrauterine growth restriction, this paper suggests a possible integration between ultrasound and molecular markers for predicting the disease in some cases. Copyright © 2003 John Wiley & Sons, Ltd. [source] Bovine fetal microchimerism in normal and embryo transfer pregnancies and its implications for biotechnology applications in cattleBIOTECHNOLOGY JOURNAL, Issue 4 2007Lauretta Turin Dr. Abstract Fetal cells and DNA have been detected in the maternal circulation during and after pregnancy in a few mammalian species. The incidence of similar microchimerism in cattle could have repercussion for the application of modern biotechnologies such as the transfer of transgenic embryos. To determine if feto-maternal leakage can occur in pregnant cows, we have analyzed maternal blood samples for the presence of fetal DNA during gestation and post-partum periods. Y chromosome-specific DNA was detected in up to 73% of blood samples from naturally mated heifers carrying conventional bull calves and a transgene-specific sequence in up to 50% of recipient cows carrying transgenic fetuses. These findings document for the first time that transplacental leakage of fetal DNA into the maternal circulation can occur in cattle despite the epitheliochorial placenta of ruminants, with potential implications for the utilization of recipient cows in the food chain. [source] | |||||||||||||