Prenatal Determination Of Fetal Sex Research Articles

Nanoparticle-Enhanced Surface Plasmon Resonance Imaging Enables the Ultrasensitive Detection of Non-Amplified Cell-Free Fetal DNA for Non-Invasive Prenatal Testing

Although many potential applications in early clinical diagnosis have been proposed, the use of a surface plasmon resonance imaging (SPRI) technique for non-invasive prenatal diagnostic approaches based on maternal blood analysis is confined. Here, we report a nanoparticle-enhanced SPRI strategy for a non-invasive prenatal fetal sex determination based on the detection of a Y-chromosome specific sequence (single-gene SRY) in cell-free fetal DNA from maternal plasma. The SPR assay proposed here allows for detection of male DNA in mixtures of 2.5 aM male and female genomic DNAs with no preliminary amplification of the DNA target sequence, thus establishing an analytical protocol that does not require costly, time-consuming, and prone to sample contamination PCR-based procedures. Afterward, the developed protocol was successfully applied to reveal male cell-free fetal DNA in the plasma of pregnant women at different gestational ages, including early gestational ages. This approach would pave the way for the establishment of faster and cost-effective non-invasive prenatal testing.

An Effective Method for Detecting Y-chromosome Specific Sequences of Circulating Fetal DNA in Maternal Plasma During the First-trimester

Background and Aims: New advances in the use of cell-free fetal DNA (cffDNA) in maternal plasma of pregnant women has provided the possibility of applying cffDNA in prenatal diagnosis as a non-invasive method. One of the applications of prenatal diagnosis is fetal gender determination. Early prenatal determination of fetal sex is required for pregnant women at risk of X-linked and some endocrine diseases. The present study was carried out to perform an efficient polymerase chain reaction (PCR) method in order to improve sensitivity, specificity and accuracy of non-invasive fetal gender detection using fetal DNA in maternal plasma during 8th -12th weeks of pregnancy. Materials and Methods: Thirty-five pregnant women with 8 to 12 weeks of pregnancy were selected for prenatal fetal sex determination. Maternal peripheral blood was collected and cffDNA was extracted from 3-ml of maternal plasma. Two multi copy Y-chromosome-specific region (DYS and DAZ) and a single copy gene (SRY) were amplified by real-time quantitative PCR. Amplification was labeled as positive, negative, or inconclusive according to a stringent algorithm. Results: Using this method, the sensitivity and specificity of the real-time PCR assay was 100% and 93.8% for prenatal fetal sex detection, respectively. Conclusions: It is concluded that fetal sex can be determined with a high level of accuracy by our algorithm, after 8 weeks of gestation with cffDNA analysis.

Non-invasive prenatal diagnostic test accuracy for fetal sex using cell-free DNA a review and meta-analysis

BackgroundCell-free fetal DNA (cffDNA) can be detected in maternal blood during pregnancy, opening the possibility of early non-invasive prenatal diagnosis for a variety of genetic conditions. Since 1997, many studies have examined the accuracy of prenatal fetal sex determination using cffDNA, particularly for pregnancies at risk of an X-linked condition. Here we report a review and meta-analysis of the published literature to evaluate the use of cffDNA for prenatal determination (diagnosis) of fetal sex. We applied a sensitive search of multiple bibliographic databases including PubMed (MEDLINE), EMBASE, the Cochrane library and Web of Science.ResultsNinety studies, incorporating 9,965 pregnancies and 10,587 fetal sex results met our inclusion criteria. Overall mean sensitivity was 96.6% (95% credible interval 95.2% to 97.7%) and mean specificity was 98.9% (95% CI = 98.1% to 99.4%). These results vary very little with trimester or week of testing, indicating that the performance of the test is reliably high.ConclusionsBased on this review and meta-analysis we conclude that fetal sex can be determined with a high level of accuracy by analyzing cffDNA. Using cffDNA in prenatal diagnosis to replace or complement existing invasive methods can remove or reduce the risk of miscarriage. Future work should concentrate on the economic and ethical considerations of implementing an early non-invasive test for fetal sex.

Isolation of trophoblast cells from transcervical specimens for prenatal determination of fetal sex by single-cell analysis

Trophoblast cells migrate from the placenta into the cervical canal early in the first trimester and can be collected in transcervical specimens (TCS). DNA isolated from these fetal cells could potentially be used for prenatal genetic diagnosis. The objectives were to 1) separate fetal cells from resident maternal cells in TCS and 2) conduct gender determination by single cell PCR.

Non-invasive prenatal diagnosis for fetal sex determination: benefits and disadvantages from the service users' perspective.

Prenatal fetal sex determination is clinically indicated for women who are at risk of having a child with a serious genetic disorder affecting a particular sex. Ultrasound has been the traditional method used, but early fetal sex determination using non-invasive prenatal diagnosis (NIPD) can now be performed using cell-free fetal DNA in maternal plasma. The study aim was to assess the views and experiences of service users who had used NIPD for fetal sex determination. In this paper, we report on the perceived benefits and disadvantages. A qualitative approach using semi-structured interviews was used. A total of 44 participants (38 women and 6 partners of participating women) were recruited. Participants' views and experiences of NIPD were overwhelmingly positive. Concerning benefits over traditional methods, three themes emerged: (1) technical aspects of technology; (2) timing; and (3) enhanced decision-making. Practical advantages of NIPD included avoiding miscarriage, and there were a number of psychological advantages associated with timing such as perceived control, early re-engagement, normalization of pregnancy and peace of mind. Participants also valued NIPD as it enabled a stepwise approach to decision-making. A number of disadvantages were discussed including concerns about social sexing and increased bonding at a time in pregnancy when miscarriage risk is high. However, participants felt these were fairly minor in comparison with the advantages of NIPD. Until definitive genetic diagnosis using NIPD is available, NIPD for fetal sex determination is perceived as a good interim measure with a number of notable advantages over traditional methods.

Noninvasive Fetal Sex Determination Using Cell-Free Fetal DNA: A Systematic Review and Meta-Analysis

Context Noninvasive prenatal determination of fetal sex using cell-free fetal DNA provides an alternative to invasive techniques for some heritable disorders. In some countries this testing has transitioned to clinical care, despite the absence of a formal assessment of performance. Objective To document overall test performance of noninvasive fetal sex determination using cell-free fetal DNA and to identify variables that affect performance. Data Sources Systematic review and meta-analysis with search of PubMed (January 1, 1997-April 17, 2011) to identify English-language human studies reporting primary data. References from review articles were also searched. Study Selection and Data Extraction Abstracts were read independently to identify studies reporting primary data suitable for analysis. Covariates included publication year, sample type, DNA amplification methodology, Y chromosome sequence, and gestational age. Data were independently extracted by 2 reviewers. Results From 57 selected studies, 80 data sets (representing 3524 male-bearing pregnancies and 3017 female-bearing pregnancies) were analyzed. Overall performance of the test to detect Y chromosome sequences had the following characteristics: sensitivity, 95.4% (95% confidence interval [CI], 94.7%-96.1%) and specificity, 98.6% (95% CI, 98.1%-99.0%); diagnostic odds ratio (OR), 885; positive predictive value, 98.8%; negative predictive value, 94.8%; area under curve (AUC), 0.993 (95% CI, 0.989-0.995), with significant interstudy heterogeneity. DNA methodology and gestational age had the largest effects on test performance. Methodology test characteristics were AUC, 0.988 (95% CI, 0.979-0.993) for polymerase chain reaction (PCR) and AUC, 0.996 (95% CI, 0.993-0.998) for real-time quantitative PCR (RTQ-PCR) (P = .02). Gestational age test characteristics were AUC, 0.989 (95% CI, 0.965-0.998) ( 20 weeks) (P = .02 for comparison of diagnostic ORs across age ranges). RTQ-PCR (sensitivity, 96.0%; specificity, 99.0%) outperformed conventional PCR (sensitivity, 94.0%; specificity, 97.3%). Testing after 20 weeks (sensitivity, 99.0%; specificity, 99.6%) outperformed testing prior to 7 weeks (sensitivity, 74.5%; specificity, 99.1%), testing at 7 through 12 weeks (sensitivity, 94.8%; specificity, 98.9%), and 13 through 20 weeks (sensitivity, 95.5%; specificity, 99.1%). Conclusions Despite interstudy variability, performance was high using maternal blood. Sensitivity and specificity for detection of Y chromosome sequences was greatest using RTQ-PCR after 20 weeks' gestation. Tests using urine and tests performed before 7 weeks' gestation were unreliable.

Noninvasive Fetal Sex Determination Using Cell-Free Fetal DNA

Noninvasive prenatal determination of fetal sex using cell-free fetal DNA provides an alternative to invasive techniques for some heritable disorders. In some countries this testing has transitioned to clinical care, despite the absence of a formal assessment of performance. To document overall test performance of noninvasive fetal sex determination using cell-free fetal DNA and to identify variables that affect performance. Systematic review and meta-analysis with search of PubMed (January 1, 1997-April 17, 2011) to identify English-language human studies reporting primary data. References from review articles were also searched. Abstracts were read independently to identify studies reporting primary data suitable for analysis. Covariates included publication year, sample type, DNA amplification methodology, Y chromosome sequence, and gestational age. Data were independently extracted by 2 reviewers. From 57 selected studies, 80 data sets (representing 3524 male-bearing pregnancies and 3017 female-bearing pregnancies) were analyzed. Overall performance of the test to detect Y chromosome sequences had the following characteristics: sensitivity, 95.4% (95% confidence interval [CI], 94.7%-96.1%) and specificity, 98.6% (95% CI, 98.1%-99.0%); diagnostic odds ratio (OR), 885; positive predictive value, 98.8%; negative predictive value, 94.8%; area under curve (AUC), 0.993 (95% CI, 0.989-0.995), with significant interstudy heterogeneity. DNA methodology and gestational age had the largest effects on test performance. Methodology test characteristics were AUC, 0.988 (95% CI, 0.979-0.993) for polymerase chain reaction (PCR) and AUC, 0.996 (95% CI, 0.993-0.998) for real-time quantitative PCR (RTQ-PCR) (P = .02). Gestational age test characteristics were AUC, 0.989 (95% CI, 0.965-0.998) (<7 weeks); AUC, 0.994 (95% CI, 0.987-0.997) (7-12 weeks); AUC, 0.992 (95% CI, 0.983-0.996) (13-20 weeks); and AUC, 0.998 (95% CI, 0.990-0.999) (>20 weeks) (P = .02 for comparison of diagnostic ORs across age ranges). RTQ-PCR (sensitivity, 96.0%; specificity, 99.0%) outperformed conventional PCR (sensitivity, 94.0%; specificity, 97.3%). Testing after 20 weeks (sensitivity, 99.0%; specificity, 99.6%) outperformed testing prior to 7 weeks (sensitivity, 74.5%; specificity, 99.1%), testing at 7 through 12 weeks (sensitivity, 94.8%; specificity, 98.9%), and 13 through 20 weeks (sensitivity, 95.5%; specificity, 99.1%). Despite interstudy variability, performance was high using maternal blood. Sensitivity and specificity for detection of Y chromosome sequences was greatest using RTQ-PCR after 20 weeks' gestation. Tests using urine and tests performed before 7 weeks' gestation were unreliable.

Non-invasive prenatal determination of fetal sex: translating research into clinical practice

The effectiveness and clinical utility of non-invasive prenatal diagnosis (NIPD) for fetal sex determination using cell-free fetal DNA (cffDNA) was assessed by undertaking a prospective national audit of UK testing. NIPD was performed using real-time polymerase chain reaction analysis of the DYS14 or SRY gene in cffDNA extracted from maternal plasma. All cases referred for fetal sex determination from 1 April 2006 to 31 March 2009 were ascertained from two laboratories offering the test. Fetal gender determined by NIPD was compared with that based on ultrasound, invasive test or phenotype at birth. Indication and rate of invasive testing was ascertained. In the first year, results were issued in 150/161 pregnancies tested. Of the 135 with outcome data, results were concordant in 130/135 [96.3% (95% CI 91.6-98.8%)]. Reporting criteria were changed and in the subsequent 511 pregnancies the concordancy rate increased to 401/403 [99.5% (95% CI 98.2-99.9%)]. Over the 3 years only 32.9% (174/528) underwent invasive testing. NIPD for fetal sex determination using cffDNA is highly accurate when performed in National Health Service laboratories if stringent reporting criteria are applied. Parents should be advised of the small risk of discordant results and possible need for repeat testing to resolve inconclusive results.

Should Human Beings Have Sex? Sexual Dimorphism and Human Enhancement

Since the first sex reassignment operations were performed, individual sex has come to be, to some extent at least, a technological artifact. The existence of sperm sorting technology, and of prenatal determination of fetal sex via ultrasound along with the option of termination, means that we now have the power to choose the sex of our children. An influential contemporary line of thought about medical ethics suggests that we should use technology to serve the welfare of individuals and to remove limitations on the opportunities available to them. I argue that, if these are our goals, we may do well to move towards a “post sex” humanity. Until we have the technology to produce genuine hermaphrodites, the most efficient way to do this is to use sex selection technology to ensure that only girl children are born. There are significant restrictions on the opportunities available to men, around gestation, childbirth, and breast-feeding, which will be extremely difficult to overcome via social or technological mechanisms for the foreseeable future. Women also have longer life expectancies than men. Girl babies therefore have a significantly more “open” future than boy babies. Resisting the conclusion that we should ensure that all children are born the same sex will require insisting that sexual difference is natural to human beings and that we should not use technology to reshape humanity beyond certain natural limits. The real concern of my paper, then, is the moral significance of the idea of a normal human body in modern medicine.

Molecular Genetic Testing of Hemophilia A

Genetic testing in hemophilia A continues to diversify. This article describes recent advances in several aspects of genetic analysis and its interpretation and reporting. The intron 1 and 22 inversions responsible for 50% of severe hemophilia A cases can be sought using long and inverse polymerase chain reaction (PCR) techniques. Point mutations are analyzed in remaining patients by PCR amplification of the F8 protein-coding region followed by either mutation screening to identify the mutated amplicon and subsequent DNA sequencing or by directly sequencing amplified DNA. Many technique modifications and sequence analysis software packages are available to reduce time and effort required to identify a mutation. Dosage analysis and gap PCR have been described to identify carriers of large F8 deletions. Noninvasive prenatal fetal sex determination and preimplantation genetic diagnosis extend the reproductive options available to hemophilia carriers. Guidelines on undertaking and reporting the testing plus external quality assessment are now available to help ensure that genetic analysis yields accurate and well-interpreted results.

Non-invasive fetal sex determination: Impact on clinical practice

Prenatal fetal sex determination is undertaken in women at high risk of serious genetic disorders affecting a specific sex. Traditionally, this is undertaken by invasive testing, usually chorionic villus sampling, which carries a risk of miscarriage of around 1%. The identification of cell-free fetal DNA in the maternal circulation has allowed the development of 'non-invasive prenatal diagnostic tests', which permit fetal sex determination without risk to the pregnancy.

Prenatal determination of fetal sex and RH D status by DNA analysis of maternal plasma

Prenatal determination of fetal sex and RH D status by DNA analysis of maternal plasma

The prenatal determination of fetal sex: Amniotic fluid testosterone as a preliminary screening test

Amniotic fluid testosterone levels were measured by radioimmunoassay without chromatography on 101 specimens obtained at amniocenteses between 15 and 19 wk gestation. For the male fetus, the amniotic fluid testosterone level of 553 ± 23 pmol/l (mean ± SE) was significantly higher ( P < 0.0005) than the concentration found for the female fetus (206 ± 9 pmol/l). There was an overlap of the ranges 74–1120 pmol/l for the male and 122–399 pmol/l for the female fetuses. Amniotic fluid testosterone levels above 400 pmol/ml were observed in 84% of the male and in none of the female fetuses. The method allowed determination of testosterone levels within 8 h. It is concluded that amniotic fluid testosterone measured by radioimmunoassay without chromatography is a rapid and effective preliminary screening test for the prenatal diagnosis of fetal sex.

Amniotic fluid testosterone in the prenatal determination of fetal sex

In the field of genetics, a rapid and accurate test for the prenatal determination of fetal sex, especially in cases of sex-linked disorders, is desirable. Amniotic fluid testosterone was measured by the radioimmunoassay technique in 37 samples obtained at saline abortion between 16 and 19 weeks' gestation. Final confirmation of fetal sex was obtained from fetal gonadal histology. In pregnancies with male fetuses, the mean amniotic fluid testosterone value of 27.6 ng. per 100 ml. was significantly higher (p < 0.001) than the mean value of 9.6 ng. per 100 ml. found in pregnancies with female fetuses. The range for pregnancies with male fetuses was 15.5 to 41.3 ng. per 100 ml. and for those with female fetuses 5.7 to 15.1 ng. per 100 ml. With a coefficient of variation of 5 to 8 per cent considered for the method of assay, there was an area of potential overlap from 12 to 18 ng. per 100 ml., giving a predictive error of approximately 16 per cent. For patients in whom the results are clearly outside the area of overlap, this test is of value as a preliminary screen in the prenatal determination of fetal sex, especially in X-linked disorders.