First-trimester Prenatal Diagnosis Research Articles

First-trimester noninvasive prenatal diagnosis of seven facioscapulohumeral muscular dystrophy type 1 families using SNP-based amplicon sequencing: An earlier, rapid and safer way.

The study is to explore the feasibility and value of SNP-based noninvasive prenatal diagnosis (NIPD) for facioscapulohumeral muscular dystrophy type 1 (FSHD1) in early pregnancy weeks. We prospectively collected seven FSHD1 families, with an average gestational age of 8+6. Among these seven couples, there were three affected FSHD1 mothers and four affected fathers. A multiplex-PCR panel comprising 402 amplicons was designed to selective enrich for highly heterozygous SNPs upstream of the DUX4 gene. Risk haplotype was constructed based on familial linkage analysis. Fetal genotypes were accurately inferred through relative haplotype dosage analysis using Bayes Factor. All tests were successfully completed in a single attempt, and no recombination events were detected. NIPD results were provided within a week, which is 4 weeks earlier than karyomapping and 7 weeks earlier than Bionano single-molecule optical mapping (BOM). Ultimately, five FSHD1 fetuses and two normal fetuses were successfully identified, with a 100% concordance rate with karyomapping and BOM. Therefore, SNP-based NIPD for FSHD1 was demonstrated to be feasible and accurate in early weeks of gestation, although the risk of recombination events cannot be completely eliminated. In the future, testing of more cases is still necessary to fully determine the clinical utility.

First-trimester prenatal diagnosis of Coffin-Siris syndrome-related congenital diaphragmatic hernia: The role of exome sequencing in determining genetic etiology.

First-trimester prenatal diagnosis of Coffin-Siris syndrome-related congenital diaphragmatic hernia: The role of exome sequencing in determining genetic etiology.

Development and validation of a haplotype-free technique for non-invasive prenatal diagnosis of spinal muscular atrophy.

ObjectiveTo develop a technique for non‐invasive prenatal diagnosis of spinal muscular atrophy and validate its performance.Study DesignPregnant women with 1 copy of SMN1 and male fetuses were enrolled. Seventeen women were included in test set A, and 10 of them were selected into test set B randomly and blinded. The two sets were tested independently by two different researchers blinded to fetal genotypes. Fetal DNA fractions were calculated based on the relative proportion of mapped chromosome Y sequencing reads. An algorithm was developed to decide fetal SMN1 copy numbers.ResultsThe concordance rate with the results of MLPA testing of amniocyte DNA was 94.12% in test set A and 90% in set B. For all tests with a classifiable result, the percent of agreement with the results of MLPA testing of amniocyte DNA was up to 100% (25/25).ConclusionWe have developed a direct, rapid, and low‐cost technique, which has a potential to be utilized for first‐trimester non‐invasive prenatal diagnosis and screening for spinal muscular atrophy with considerable reliability and feasibility.

Prenatal diagnosis of Duchenne and Becker muscular dystrophies: Underestimated problem of the secondary prevention of monogenetic disorders.

The aim of this study was to analyze the influence of effective preconceptional testing for carrier status in women at risk for Duchenne and Becker muscular dystrophies (D/BMD) on the prenatal diagnosis. A retrospective analysis of 201 prenatal tests was performed in 169 Polish women at risk, in regard to time of testing for carrier status (prior to conception or during pregnancy) and carrier status of tested women, including confirmed D/BMD carriers (n = 78; 46.2%), D/BMD non-carriers - tested for germline mosaicism risk (n = 23; 13.6%), and women at risk with uncertain carrier status (n = 68; 40.2%). Only 52.7% of women were tested for D/BMD carrier status prior to conception and in these women prenatal diagnosis was carried out more frequently in the first trimester of pregnancy (64.7% vs 47.8%; P = 0.035). The results of prenatal testing in male fetuses in pregnancies of confirmed D/BMD carriers and D/BMD non-carriers - tested for germline mosaicism risk were conclusive in all cases, whereas in women with uncertain carrier status, only 60.0% of results were conclusive. Eighty-five of 103 female fetuses (82.5%) were tested prenatally and in 31.8% of them fetal carrier status was confirmed. Carrier status testing in women prior to conception has a positive impact on the frequency of first-trimester prenatal diagnosis and known D/BMD carrier status on the effectiveness of prenatal diagnosis. Due to the low percentage of women tested effectively prior to conception, carrier status testing in the families at risk should be propagated (including possibility of prenatal diagnosis of female fetuses).

Cytogenetic follow-up of chromosomal mosaicism detected in first-trimester prenatal diagnosis

To contribute to the risk assessment of true fetal mosaicism after detection of a mosaic chromosomal anomaly in chorionic villus samples (CVS) in order to enable more effective counseling and pregnancy management. We retrospectively reviewed 7112 consecutive CVS analyzed on both direct preparations and cultured cells. In 135 out of the 177 cases of mosaicism, we performed cytogenetic follow-up and determined the frequency of confined placental mosaicism (CPM) and true fetal mosaicism according to type and distribution of the cytogenetic abnormality. True fetal mosaicism was detected in 38 out of 135 cases (28.15%), confirming the higher incidence of CPM (71.85%). Confirmation rate of CV mosaicism depends on the combination of placental cell lineages affected, chromosome involved and mosaic versus non-mosaic chromosomal anomaly. The overall probability of fetal involvement significantly rises with involvement of mesenchymal cells: 5.88% abnormal cytotrophoblast, 20.96% abnormal mesenchyme and 58.97% anomalies in both tissues. Most of the mosaic findings at CVS are unreliable indicators of the fetal karyotype. Our study contributes to large series with cytogenetic information from the different tissues along the cytotrophoblast-extraembrional mesoderm-fetus axis in order to infer clinical relevance of the findings and to enable more effective genetic counseling.

Including ethical considerations in models for first-trimester screening for pre-eclampsia

Recent efforts to develop reliable and efficient early pregnancy screening programmes for pre-eclampsia have focused on combining clinical, biochemical and biophysical markers. The same model has been used for first-trimester screening for fetal aneuploidies i.e. prenatal diagnosis (PD), which is routinely offered to all pregnant women in many developed countries. Some studies suggest combining PD and pre-eclampsia screening, so women can be offered testing for a number of conditions at the same clinical visit. A combination of these tests may be practical in terms of saving time and resources; however, the combination raises ethical issues. First-trimester PD and pre-eclampsia screening entail qualitative differences which alter the requirements for disclosure, non-directedness and consent with regard to the informed consent process. This article explores the differences related to the ethical issues raised by PD and pre-eclampsia in order to elucidate which factors are relevant to deciding the type of information and consent required in each context from the perspective of the ethical principles of beneficence and autonomy. Furthermore, it argues that ensuring respect for patient autonomy is context dependent and, consequently, pre-eclampsia screening and PD should be performed independently of one another.Pre-eclampsia is a complication of pregnancy that threatens the health of both mother and baby. It has recently been discovered that aspirin is an effective treatment of pre-eclampsia, but only if the mother starts taking aspirin before the 12th week of pregnancy. Presently, much research into the development of a method of screening for pre-eclampsia, similar to that currently used to detect Down’s syndrome during pregnancy, is underway. Some studies have suggested combining the Down’s syndrome and pre-eclampsia screening tests during the first trimester of pregnancy. There are good reasons for this as the time frame for testing is the same and some of the same components can be used in both tests. However, in this paper, we analyse the types of risk and benefits associated with both tests and we find that the type of information required for patients to give consent, and the type of consent required (written, verbal or implicit), are not the same. We find it problematic to combine these tests, and we recommend performing each test independently of the other.

Response to “QF‐PCR as a substitute for karyotyping of cytotrophoblast for the analysis of chorionic villi: advantages and limitations from a cytogenetic retrospective audit of 44 727 first‐trimester prenatal diagnoses”

Response to “QF‐PCR as a substitute for karyotyping of cytotrophoblast for the analysis of chorionic villi: advantages and limitations from a cytogenetic retrospective audit of 44 727 first‐trimester prenatal diagnoses”

First-trimester prenatal diagnosis of Ellis–van Creveld syndrome

ObjectiveTo present the perinatal findings and first-trimester molecular and transabdominal ultrasound diagnosis of a fetus with Ellis–van Creveld (EvC) syndrome. Case ReportA 35-year-old woman was referred for genetic counseling at 13 weeks of gestation because of a family history of skeletal dysplasia. She had experienced one spontaneous abortion, and delivered one male fetus and one female fetus with EvC syndrome. During this pregnancy, a prenatal transabdominal ultrasound at 13+4 weeks of gestation revealed a nuchal translucency (NT) thickness of 2.0 mm, an endocardial cushion defect, postaxial polydactyly of bilateral hands, and mesomelic dysplasia of the long bones. Amniocentesis was performed at 13+5 weeks of gestation. Results of a cytogenetic analysis revealed a karyotype of 46,XX and that of a molecular analysis revealed compound heterozygous mutations of c.1195C>T and c.871-2_894del26 in the EVC2 gene. Prenatal ultrasound at 16 weeks of gestation showed a fetus with short limbs, an endocardial cushion defect, and postaxial polydactyly of bilateral hands. The parents decided to terminate the pregnancy, and a 116-g female fetus was delivered with a narrow thorax, shortening limbs, and postaxial polydactyly of the hands. ConclusionPrenatal diagnosis of an endocardial cushion defect with postaxial polydactyly should include a differential diagnosis of EvC syndrome in addition to short rib–polydactyly syndrome, Bardet–Biedl syndrome, orofaciodigital syndrome, Smith–Lemli–Opitz syndrome, and hydrolethalus syndrome.

First-trimester prenatal diagnosis performed on pregnant women with fetal ultrasound abnormalities: The reliability of interphase fluorescence in situ hybridization (FISH) on mesenchymal core for the main aneuploidies

Objectives To examine the reliability of interphase FISH analysis of the main aneuploidies performed on mesenchymal core when prenatal diagnosis was performed on pregnant women with first-trimester fetal abnormalities on ultrasound. Study design 386 first-trimester prenatal examinations were investigated from chorionic villus samplings for increased nuchal translucencies or other fetal ultrasound abnormalities. Interphase fluorescence in situ hybridization (FISH) for the main aneuploidies (trisomies 13, 18, 21 and gonosomal aneuploidies) was performed on the mesenchymal core of villi. Molecular cytogenetic results were always complemented by conventional cytogenetic results on long-term cultured villi (LTC-villi). Short-term cultured villi (STC-villi) preparations were retrospectively performed only when a chromosomal abnormality was observed with interphase FISH and/or LTC-villi. Results 88 chromosomal abnormalities (88/386 = 22.8% of first-trimester diagnoses) which could discuss subsequent abortions were observed after LTC-villi preparations. All cases possibly detectable by interphase FISH were detected. Thus, 85 aneuploidies (85/386 = 22.0% of first-trimester diagnoses; 85/88 = 96.6% of chromosomal abnormalities) were detected by interphase FISH, allowing early abortion by curettage before week 14 amenorrhea. No discrepancy occurred between interphase FISH and LTC-villi results for the aneuploidies studied. Three false-negative results (3/386 = 0.77% of first-trimester diagnoses; 3/88 = 3.41% of chromosomal abnormalities) were observed with STC-villi. Conclusion We observed a high rate of false-negative results on cytotrophoblast cells. Conversely, interphase FISH of the main aneuploidies on the mesenchymal core provided rapid and reliable results, and therefore should be preferred to STC-villi in first-trimester prenatal diagnosis performed on pregnant women with fetal abnormalities on ultrasound.

Immunofluorescence Analysis of Villous Trophoblasts: A Tool for Prenatal Diagnosis of Inherited Epidermolysis Bullosa with Pyloric Atresia

Genetic mutations invalidating the genes for integrin alpha6beta4 and, in some cases, plectin are associated with junctional and simplex epidermolysis bullosa with pyloric atresia (PA-JEB and PA-EBS), respectively. These recessive inherited conditions are characterized by pregnancies with fetal bullae, pyloric atresia, polyhydramnios, and neonatal mucocutaneous blistering, which often results in early postnatal demise. To date, first-trimester DNA-based prenatal diagnosis is not applicable to affected kindred carrying as yet unidentified genetic mutations. Here, we show that first-trimester chorionic villi strongly express both integrin alpha6beta4 and plectin, which persist throughout the pregnancy. Based on this observation, we implemented 25 prenatal diagnoses in kindred at risk for PA-EB by immunomapping, which identified three PA-JEB-affected fetuses and 22 healthy ones. In 19 cases, including the three PA-JEB pregnancies that were prematurely terminated, the results were confirmed by chorionic villous DNA-based tests, which also led to the identification of seven previously unreported mutations in the alpha6beta4 integrin genes. Our prediction was further sustained by the birth of 22 healthy babies. These results validate chorionic villi immunofluorescence examination as a tool for prenatal diagnosis of PA-JEB and PA-EBS and indicate that this procedure could be devised for EB with muscular dystrophy, which is also associated with genetic mutations in plectin.

Breast cancer risk assessment by Gail model in Iranian patients: accuracy and limitations

Cytogenetic prenatal diagnosis on chorionic villi (CV) can be complicated by the detection of “chromosomal mosaicism.” This is one of the main issues of first-trimester cytogenetic prenatal diagnosis as it can involve different types of chromosomal abnormalities, and the prediction of the fetal involvement is challenging because the detected abnormal mosaic cell line is not necessarily extended to fetal tissues. In addition, because the cell-free fetal DNA that is targeted by the new technologies for fetal aneuploidy risk assessment is mainly derived from the CV cells, the same challenges related to chromosomal mosaicism can be transferred into this new clinical field. This review illustrates the phenomenon of fetoplacental mosaicism, the management of prenatal diagnosis cases complicated by the detection of such a biological phenomenon, and the implications of its presence for the management of high-risk cfDNA testing results for fetal aneuploidies.

Prenatal diagnosis of β‐thalassemia in Southern Punjab, Pakistan

Pakistan has a large population of more than 150 million people with an overall carrier frequency of approximately 5.6% for beta-thalassemia. Punjab is the largest province of the country having more than 50% of the population. The state of beta-thalassemia is alarming as consanguinity is very high (>81%) and the literacy rate is low in South Punjab. A thalassemia prevention program is the need of the hour in this part of Pakistan. In this study, we initiated awareness, screening, and characterization of the mutations causing beta-thalassemia as well as a genetic counseling program mainly in the districts of Faisalabad and D.G. Khan to establish prenatal diagnosis, a facility previously unavailable in this region for disease prevention. A total of 248 unrelated transfusion-dependent children and the available members of their families were screened to characterize the mutations and identify the carriers. Genetic counseling was provided to these families and prenatal diagnosis offered. In the samples analyzed, 11 beta-thalassemia mutations and three hemoglobin variants were detected mainly by using the Monoplex and Multiplex ARMS-PCR. First-trimester prenatal diagnosis was carried out through chorionic villus sampling (CVS) in seven pregnancies at risk. As a result of our campaign, 145 carrier couples planning to have more children gave their consent to have retrospective prenatal diagnosis in every pregnancy in future. A cooperative trend and a positive attitude toward the prevention of beta-thalassemia were noticed in the families with affected children and in the general population.

Gestational age at abortion: The impact of first-trimester risk assessment for aneuploidy

The purpose of this study was to determine the impact of first-trimester risk assessment on gestational age at abortion for abnormal fetal karyotype. Women who had abortion for trisomies 21, 18, and 13, 45X, and Triploidy in our hospital from 1999 to 2005 were included. Data collected included gestational age at abortion, method of prenatal diagnosis, and whether or not first-trimester risk assessment was performed. Analysis was performed using Spearman Correlation, Chi-square for trend, Fisher exact test, and Mann-Whitney U test. One hundred forty-nine patients were included. There was an inverse correlation between year of abortion and gestational age (rho = -0.31; P < .001) coinciding with significant increases in the rates of first-trimester risk assessment and prenatal diagnosis by chronic villus sampling. First-trimester risk assessment is associated with earlier diagnosis of aneuploidy. In our institution, this has led to earlier abortions. Availability of quality first-trimester risk assessment can decrease the need for abortion later in pregnancy.

Is the DNA Sequence the Gold Standard in Genetic Testing? Quality of Molecular Genetic Tests Assessed

Molecular genetic testing is a fast-growing diagnostic discipline. Only a few decades have passed since Kan and Dozy (1) described the first DNA test, which used a restriction enzyme digestion to test for sickle cell disease, and my group (2) reported the first use of linked DNA markers for first-trimester prenatal diagnosis of Duchenne muscular dystrophy. Since then, molecular genetic testing with direct or indirect mutation detection has been widely applied to confirm the clinical diagnosis for many monogenetic disorders and to determine carrier status. It also has been applied to predict presymptomatic cases and to predict, early in pregnancy, whether a fetus will be affected with a severe disorder. Because the complete human genome (sequence) became available in 2003, molecular genetic testing will be applied more widely every day. Risk assessments for multifactorial disorders will gain more attention, as will predictions of genotypes that increase the possibility of adverse outcomes when certain drugs are used (pharmacogenomics). Genetic information usually does not change throughout an individual’s life; therefore, the sequence of a gene need be determined only once in a person’s lifetime. For this reason, the outcome of a genetic test should be unambiguous, time resistant, and universal in nomenclature. The “DNA sequence of a gene” or “of a gene region” is often perceived as the ultimate result of a molecular genetic test. If we consider the nucleotide (A, T, G, or C) as the “SI unit” for DNA, then a nucleotide sequence comes as close to a gold standard as one can get in terms of a …

First-trimester prenatal diagnosis in haemophilia A and B families—10 years experience from a centre in India

During the last 10 years (1995-2005) we have offered diagnosis in 438 families out of 502 families referred, by chorionic villus sampling procedure between 10 and 12 weeks of pregnancy in severe haemophilia A and B families. Sixty four families could not be offered a diagnosis in the first trimester either due to non-informativeness with the available techniques or due to the absence of affected members in the family and were subsequently offered diagnosis in the second trimester by direct analysis of factor VIII/IX clotting activity and antigen in the fetal blood samples. For first-trimester diagnosis in the chorionic villus samples, we have used both direct and indirect methods, that is, intron 22 and 1 inversions in the factor VIII gene, a multiplex PCR for the detection of gross deletions in the factor IX gene and RFLP analysis using a battery of markers within and outside the factor VIII/IX gene. The informativeness of all these techniques was found to be 92.21% in case of haemophilia A and 83.91% in case of haemophilia B. We followed up 122 children out of 326 (diagnosed unaffected prenatally) after birth and the diagnosis was adequately reconfirmed by both factor assays and by DNA analysis. Only one case of misdiagnosis was detected so far (0.22%), where the diagnosis was based only on the extragenic marker of the factor VIII gene.

New haplotype for the Glu104Asp mutation in triose‐phosphate isomerase deficiency and prenatal diagnosis in a Spanish family

First-trimester prenatal diagnosis was undertaken by chorionic villus DNA analysis in a Spanish family with the inherited Glu104Asp triose-phosphate isomerase deficiency. The fetus was heterozygous for the mutation and therefore predicted to be clinically unaffected. To investigate the evolutionary origin of this mutation, studies were conducted on the intragenic 2262A/G polymorphism and the CD4 pentameric tandem repeat marker. A different haplotype was found to the one previously described, suggesting a different origin of the Spanish mutation.

DNA-based prenatal diagnosis for severe and variant forms of multiple acyl-CoA dehydrogenation deficiency

Multiple acyl-CoA dehydrogenation deficiency (MADD) is a clinically heterogeneous disorder of mitochondrial fatty acid, amino acid, and choline oxidation due to mutations in the genes encoding electron transfer flavoprotein (ETF) or ETF ubiquinone oxidoreductase (ETFQO). So far, prenatal diagnosis of MADD has relied mostly on second-trimester biochemical analyses of amniotic fluid or cultured amniocytes. We report here on an alternative DNA-based approach for prenatal diagnosis in pregnancies at risk of MADD. We used our knowledge of the mutational status in three unrelated families with a history of MADD to perform direct sequencing for the familial mutations using genomic DNA isolated from chorionic villus samples (CVS) at gestational week 10 to 11. Within two days, we were able to carry out accurate DNA-based prenatal testing in one pregnancy at risk of severe MADD, and in two pregnancies at risk of variant forms of MADD. This is the first report of DNA-based prenatal diagnosis of MADD. Our molecular approach is suitable for fast and reliable first-trimester prenatal diagnosis in pregnancies at risk of severe and variant forms of MADD.

Prenatal diagnosis for arginase deficiency by second‐trimester fetal erythrocyte arginase assay and first‐trimester ARG1 mutation analysis

Hyperargininemia is a progressive neurometabolic disorder caused by deficiency of hepatic cytosolic arginase I, resulting from mutations in the ARG1 gene. We diagnosed arginase deficiency in a three-year-old male child of first-cousin Palestinian Arab parents. Prenatal diagnosis of an unaffected fetus was achieved in the second trimester of a subsequent pregnancy by cordocentesis and analysis of arginase activity in fetal erythrocytes. ARG1 mutation analysis in the proband revealed homozygosity for a deletion of 10,753 bp extending from the first intron to beyond the poly (A) site of the gene. This is the first gross deletion in the ARG1 gene to be identified and the first mutation to be described in an arginase-deficient patient of this ethnic origin. The identification of the ARG1 deletion in this family enabled first-trimester prenatal diagnosis in a subsequent pregnancy by multiplex PCR analysis performed on chorionic villous DNA.

Utilization of prenatal genetic testing by Israeli Moslem women: a national survey.

The number of prenatal genetic tests that are being offered to women is constantly increasing. However, there is little national data as to who is performing the tests and the reasons for doing or not doing so. The aim of the study was to evaluate the proportion of Israeli Moslem women who perform the various prenatal genetic tests and the factors affecting the performance of these tests. A 2-day survey was conducted in all the maternity departments in Israel based on a structured interview. Of the 242 women interviewed, 74.2% underwent the triple test (TT), 15.8% of the women older than 35 years who were eligible to take the test free of charge underwent amniocentesis and only 1.5% underwent fragile-X (FX) carrier testing which costs 100 dollars privately. In the stepwise regression analysis, having fewer children and having had a higher education affected the performance of the TT. None of the sociodemographic factors were associated with the performance of amniocentesis or FX carrier testing, but the sample sizes were small. The main reason reported by the women for not performing the TT and FX carrier testing was not being referred for testing. The main reason for not performing amniocentesis was that they chose not to perform the test (the majority of these women were religious or ultrareligious). Consideration should be given to providing first-trimester prenatal diagnosis when termination of pregnancy in the Moslem population is more acceptable. In addition, consideration should be given to including state-subsidized FX testing as there is a low rate of FX testing partly due to the cost. Primary care givers should be educated about the importance of prenatal genetic testing.

Prenatal diagnosis of JAK3 deficient SCID

The JAK3 gene, encoding a tyrosine kinase functionally coupled to cytokine receptors which share the common gamma chain, has been identified as the defective gene for autosomal recessive severe combined immunodeficiency (SCID). Thus, specific mutational diagnosis has become possible. We screened all exons with a combined single strand conformational polymorphism and hetero-duplex formation assay followed by sequence analysis to identify specific mutations in two families. This assay was used on chorionic villus sampling derived DNA in two fetuses from two unrelated families, where we found mutations in both parents. We were able to exclude the mutations in both fetuses by the 12th week of gestation. The described method for first-trimester prenatal diagnosis of autosomal recessive T-B+SCID provides a valid tool to aid in genetic counselling and possibly prenatal therapy in this disease.