Amniocentesis and chorionic villus sampling

Noninvasive Prenatal Screening for Common Fetal Aneuploidies Using Single-Molecule Sequencing

Amplification biases caused by next-generation sequencing (NGS) for noninvasive prenatal screening (NIPS) may be reduced using single-molecule sequencing (SMS), during which PCR is omitted. Therefore, the performance of SMS-based NIPS was evaluated. We used SMS-based NIPS to screen for common fetal aneuploidies in 477 pregnant women. The sensitivity, specificity, positive predictive value, and negative predictive value were estimated. The GC-induced bias was compared between the SMS- and NGS-based NIPS methods. Notably, a sensitivity of 100% was achieved for fetal trisomy 13 (T13), trisomy 18 (T18), and trisomy 21 (T21). The positive predictive value was 46.15% for T13, 96.77% for T18, and 99.07% for T21. The overall specificity was 100% (334/334). Compared with NGS, SMS (without PCR) had less GC bias, a better distinction between T21 or T18 and euploidies, and better diagnostic performance. Overall, our results suggest that SMS improves the performance of NIPS for common fetal aneuploidies by reducing the GC bias introduced during library preparation and sequencing.

Identification of a novel gene signature in second-trimester amniotic fluid for the prediction of preterm birth

Preterm birth affects approximately 5% to 7% of live births worldwide and is the leading cause of neonatal morbidity and mortality. Amniotic fluid supernatant (AFS) contains abundant cell-free nucleic acids (cfNAs) that can provide genetic information associated with pregnancy complications. In the current study, cfNAs of AFS in the early second-trimester before the onset of symptoms of preterm birth were analyzed, and we compared gene expression levels between spontaneous preterm birth (n = 5) and term birth (n = 5) groups using sequencing analysis. Differential expression analyses detected 24 genes with increased and 6 genes with decreased expression in the preterm birth group compared to term birth. Upregulated expressions of RDH14, ZNF572, VOPP1, SERPINA12, and TCF15 were validated in an extended AFS sample by quantitative PCR (preterm birth group, n = 21; term birth group, n = 40). Five candidate genes displayed a significant increase in mRNA expression in immortalized trophoblast HTR-8/SVneo cell with H₂O₂ treatment. Moreover, the expression of five candidate genes was increased to more than twofold by pretreatment with lipopolysaccharide in HTR-8/SVneo cells. Changes in gene expression between preterm birth and term birth is strongly correlated with oxidative stress and infection during pregnancy. Specific expression patterns of genes could be used as potential markers for the early identification of women at risk of having a spontaneous preterm birth.

InUtero Gene Therapy: Progress and Challenges

In utero gene therapy has the potential to treat lethal and morbid perinatal diseases before birth. Small fetal size, a tolerogenic immune system, and dosing efficiency make the fetus a compelling patient. Numerous clinical, social, and institutional factors must be considered to achieve the promise of genetic treatment before birth.

Functional analysis of cell-free RNA using mid-trimester amniotic fluid supernatant in pregnancy with the fetal growth restriction

The prediction and monitoring of fetal growth restriction (FGR) fetuses has become with the use of ultrasound. However, these tools lack the fundamental evidence for the growth of fetus with FGR excluding pathogenic factors.Amniotic fluid samples were obtained from pregnant women for fetal karyotyping and genetic diagnosis at 16 to 19 weeks of gestation. For this study, 15 FGR and 9 control samples were selected, and cell-free fetal RNA was isolated from each supernatant of the amniotic fluid for microarray analysis.In this study, 411 genes were differentially expressed between the FGR and control group. Of these genes, 316 genes were up-regulated, while 95 genes were down-regulated. In terms of gene ontology, the up-regulated genes were highly related to metabolic process as well as protein synthesis, while the down-regulated genes were related to receptor activity and biological adhesion. In terms of tissue-specific expression, the up-regulated genes were involved in various organs while down-regulated genes were involved only in the brain. In terms of organ-specific expression, many genes were enriched for B-cell lymphoma, pancreas, eye, placenta, epithelium, skin, and muscle. In the functional significance of gene, low-density lipoprotein receptor-related protein 10 (LRP10) was significantly increased (6-fold) and insulin-like growth factor (IGF-2) was dramatically increased (17-fold) in the FGR cases.The results show that the important brain-related genes are predominantly down-regulated in the intrauterine growth restriction fetuses during the second trimester of pregnancy. This study also suggested possible genes related to fetal development such as B-cell lymphoma, LRP10, and IGF-2. To monitor the fetal development, further study may be needed to elucidate the role of the genes identified.

A Proof-of-Concept Case Study for Personalized Noninvasive Prenatal Diagnosis: Can We Put It to Work?

This commentary highlights the article by van den Oever et al that describes a new method of prenatal diagnosis of single-mutation disorders.

Non-invasive prenatal diagnostics of aneuploidy using next-generation DNA sequencing technologies, and clinical considerations

Rapidly developing next-generation sequencing (NGS) technologies produce a large amount of data across the whole human genome and allow a large number of DNA samples to be analyzed simultaneously. Screening cell-free fetal DNA (cffDNA) obtained from maternal blood using NGS technologies has provided new opportunities for non-invasive prenatal diagnosis (NIPD) of fetal aneuploidies. One of the major challenges to the analysis of fetal abnormalities is the development of accurate and reliable algorithms capable of analyzing large numbers of short sequence reads. Several such algorithms have recently been developed. Here, we provide a review of recent NGS-based NIPD methods as well as the available algorithms for short-read sequence analysis. We furthermore introduce the practical application of these algorithms for the detection of different types of fetal aneuploidies, and compare the performance, cost and complexity of each approach for clinical deployment. Our review identifies several main technologies and trends in NGS-based NIPD. The main considerations for clinical development for NIPD and screening tests using DNA sequencing are: accuracy, intellectual property, cost and the ability to screen for a wide range of chromosomal abnormalities and genetic defects. The cost of the diagnostic test depends on the sequencing method, diagnostic algorithm and volume of the tests. If the cost of sequencing equipment and reagents remains at or around current levels, targeted approaches for sequencing-based aneuploidy testing and SNP-based methods are preferred.

IGF-I and NEFA concentrations in fetal fluids of term pregnancy dogs

Insulin-like growth factor-I (IGF-I) and non-esterified fatty acids (NEFA) play an essential role in fetal growth and development. To date, fetal fluids IGF-I and NEFA levels at term canine pregnancy are unknown and could be related to the neonatal development and breed size. For these reasons, the aims of the present study were as follows: (1) to evaluate IGF-I and NEFA concentrations in fetal fluids collected from normally developed and viable newborn puppies born at term of normal pregnancies; (2) to assess possible differences between IGF-I and NEFA levels in amniotic compared with allantoic fluid; (3) to detect possible relationship between breed body size and IGF-I and NEFA amniotic and allantoic concentrations; (4) to evaluate possible differences in IGF-I fetal fluids levels between male and female puppies; and (5) to assess possible correlations between the two hormones in each type of fluid. The study enrolled 25 pure breed bitches submitted to elective Cesarean section at term because of the high risk of dystocia or previous troubles at parturition. At surgery, amniotic and allantoic fluids were collected and assayed for IGF-I and NEFA. IGF-I and NEFA amounts in both amniotic and allantoic fluids of different breed size bitches (small: ≤10 kg; medium: 11-25 kg; large: 26-40 kg) were detected, as well as the effect of gender on IGF-I levels. On a total of 73 amniotic and 76 allantoic samples collected by normal, viable, and mature newborns, the mean IGF-I concentration was significantly higher in amniotic than in allantoic fluid in all three groups, but the amniotic IGF-I levels were significantly lower in small and medium size bitches when compared with large ones. No significant differences were found in allantoic IGF-I concentrations among size groups. A significant effect of the puppy gender on IGF-I content in both fetal fluids was not reported. Regarding NEFA, in all the three groups, the mean NEFA concentration did not significantly differ between amnion and allantois, but in both fetal fluids, higher NEFA levels were detected in samples belonging to small breeds when compared with medium and large. These data strongly indicated that, also in the dog, a relation between fetal fluids IGF-I and NEFA concentrations and breed size exists. Further research is needed to elucidate the possible role of IGF-I and NEFA in the pathologic conditions related to canine fetal growth.

Implementing non-invasive RHD genotyping on cell-free foetal DNA from maternal plasma: the Pavia experience

BACKGROUND

The occurrence of cell-free foetal DNA in maternal circulation opens new possibilities in non-invasive antenatal diagnosis. Real-time polymerase chain reaction (PCR) analysis is an useful approach to foetal RhD blood group determination, thus being important in the prevention of haemolytic disease of foetus and new-born (HDFN).

STUDY DESIGN AND METHODS

Using real-time PCR assays we typed 20 samples of plasma, provided in a blinded fashion, from the International Reference Laboratory, two plasma samples sent by the "2010 Workshop on Molecular Blood Group Genotyping"; seven samples from D-negative mothers at the 16th week of gestation provided by our Hospital as prospective validation cases, and two plasma samples received from the "1(st) Collaborative study establishing the sensitivity standard for non-invasive prenatal determination of foetal RHD genotype". To confirm the RHD typing of the seven prospective samples, PCR with sequence specific primers (PCR-SSP) was applied on genomic DNA from amniocytes (5 cases) and paternal peripheral blood (2 cases).

RESULTS

The results for the 31 investigated samples showed 100% concordance. Our measurable benefits were: confidence with a new technology, awareness of having gained the European standard level and increased self-assurance regarding the introduction of this typing technique in prenatal diagnostics.

DISCUSSION

These results demonstrate the feasibility and accuracy of our validation protocol. RHD typing on cell-free foetal DNA is a procedure which requires particular care and a great degree of expertise for diagnostic use. International collaborations are essential for monitoring the performance of laboratories in the absence of specific quality control programmes.

Manifestações clínicas e fonoaudiológicas na Síndrome de Turner: estudo bibliográfico

TEMA: síndrome genética e achados fonoaudiológicos. OBJETIVO: descrever as manifestações clínicas e fonoaudiológicas em indivíduos com a Síndrome de Turner CONCLUSÃO: foram levantados 23 artigos sobre a Síndrome de Turner dos quais 7 discorriam sobre a audição e suas alterações nesses indivíduos, 6 sobre linguagem receptiva e/ou expressiva e praxia, 5 sobre aspectos psicológicos e cognitivos além de 28 artigos referentes às manifestações clínicas em geral. Por meio do levantamento bibliográfico pode-se observar que as manifestações fonoaudiológicas na Síndrome de Turner são pouco estudadas e, dentro da fonoaudiologia as manifestações audiológicas como perda de audição e otites são as mais estudadas, ao contrário dos aspectos práxicos e de recepção/ expressão da linguagem.

Prenatal diagnosis of cystic fibrosis: the 18-year experience of Brittany (western France)

OBJECTIVE

This study reports 18 years of experience in prenatal diagnosis (PD) of cystic fibrosis (CF) in a region where CF is frequent and the uptake of PD is common (Brittany, western France).

METHOD

All PDs made over the period 1989-2006 in women living in Brittany were collected.

RESULTS

We recorded 268 PDs made in 1 in 4 risk couples, plus 22 PDs directly made following the sonographic finding of echogenic bowel. Most of the 268 PDs were done in couples already having CF child(ren) (n = 195, 72.8%). Close to one-fifth followed cascade screening (n = 49, 18.3%), which identified 26 new 1 in 4 risk couples among the relatives of CF patients or of carriers identified through newborn screening (NBS). The remaining PDs were mainly made in couples whose 1 in 4 risk was evidenced following the diagnosis of echogenic bowel in a previous pregnancy (n = 22, 8.2%). Although patients' life expectancy has considerably improved, in our population the great majority of couples chose pregnancy termination when PD indicated that the foetus had CF (95.9%).

CONCLUSION

This study describes the distribution of PDs according to the context in which the 1 in 4 risk was discovered and highlights the real decisions of couples as regards pregnancy termination after a positive PD.

Medical legal issues in prenatal diagnosis

The capacity to diagnose fetal disease or abnormality continues to grow, especially in the genetic definition of the fetus. With this growth have come claims of medical malpractice that have mostly centered on a failure of informed consent. Failure may occur by omission or failed communication of pertinent information to the parents or by alleged error in the interpretation of diagnostic information. The usual claim against a physician or other provider is not that of causing damage or disease in the fetus but of causing a loss of opportunity to prevent conception or live birth of an infant who has an abnormality. Successful suits for "wrongful birth," brought by parents of an abnormal child, are common in many United States jurisdictions, but suits for "wrongful life," brought on behalf of the child, have usually been denied.

Multinucleated foreign body giant cells in placental membrane

We report the pathologic finding of a multinucleated foreign body giant cell reaction to squames and fetal hair in the placental membranes in a 37-week 1-day intrauterine gestation. This reaction appeared to have developed in association with repeated intrauterine procedures performed in the third trimester, including cordocentesis for fetal blood sampling, intrauterine blood transfusion, and amnioreduction for polyhydramnios. This type of reaction most likely was directed to prolonged amniotic fluid leakage that occurred spontaneously or after intrauterine procedures in the second half of the second trimester and the third trimester. Careful examination of the placental membranes and recognition of the foreign body giant cell reaction may provide etiologic insight in cases of unexplained oligohydramnios.

Amniotic fluid: not just fetal urine anymore

Amniotic fluid (AF) is a complex substance essential to fetal well-being. This article reviews recent discoveries and the current understanding of the origin and circulation of AF and its nutritive, protective, and diagnostic functions. Future directions for AF research are also discussed.

Large-scale pre-diagnosis study of fetal RHD genotyping by PCR on plasma DNA from RhD-negative pregnant women

BACKGROUND

The routine prenatal determination of fetal RhD blood group would be very useful in the management of pregnancies in RhD-negative women, as up to 40% of these pregnancies bear a RhD-negative fetus. The fetal DNA present in maternal plasma offers an opportunity for risk-free prenatal diagnosis.

AIM

This study focused on the feasibility and accuracy of large-scale RhD fetal diagnosis in non-immunized and anti-D immunized RhD-negative women.

METHODS

Plasma DNA was extracted from 893 RhD-negative pregnant women and amplified in exons 7 and 10 of the RHD gene using conventional and real-time PCR. The results were then compared with the RHD fetal genotype determined on amniotic cells and/or the RhD phenotype of the red blood cells of the infants at birth.

RESULTS

After exclusion of 42 samples from women exhibiting a nonfunctional or rearranged RHD gene, fetal RhD status was predicted with a 99.5% accuracy. A strategy is also proposed to avoid the small number of false-positive and -negative results.

CONCLUSION

Fetal RHD genotyping from maternal plasma DNA in different clinical situations may be used with confidence.

Fetal blood group genotyping from DNA from maternal plasma: an important advance in the management and prevention of haemolytic disease of the fetus and newborn

The cloning of blood group genes and subsequent identification of the molecular bases of blood group polymorphisms has made it possible to predict blood group phenotypes from DNA with a reasonable degree of accuracy. The major application of this technology, which has now become the standard of care, is the determination of a fetal RHD genotype in women with anti-D, to assess whether the fetus is at risk of haemolytic disease of the fetus and newborn (HDFN). Initially, the procurement of fetal DNA required the invasive procedures of amniocentesis or chorionic villus sampling. Since the discovery of fetal DNA in maternal plasma in 1997, the technology of detecting an RHD gene in this very small quantity of fetal DNA has developed rapidly, so that non-invasive fetal D typing can now be provided as a diagnostic service for D-negative pregnant women with anti-D. Within a few years, it is probable that fetuses of all D-negative pregnant women will be tested for RHD, to establish whether the mother requires antenatal anti-D immunoglobulin prophylaxis.

A report of early (13 + 0 to 14 + 6 weeks) and mid-trimester amniocenteses: 10 years' experience

OBJECTIVE

To report in singleton pregnancies the post-procedure safety and maternal complications of early amniocenteses performed between 13 + 0 and 14 + 6 weeks of gestation and mid-trimester amniocenteses performed between 15 + 0 and 18 + 6 weeks of gestation.

METHODS

The study was carried out at the Prenatal Diagnosis Center, Siena University, Italy, during a 10-year period, following the Regional Protocol for Prenatal Diagnosis. Our study population included 3769 amniocenteses, 475 early and 3294 mid-trimester. Complications considered included miscarriage (immediately after the procedure and until 24 weeks of gestation), blood-stained amniotic fluid, failed cell culture, amniotic fluid leakage, preterm premature rupture of the membranes (PROM), preterm delivery and presence of neonatal talipes equinovarous.

RESULTS

Cytogenetic anomalies were found in 111 cases (2.9%), 18 occurring early and the other 93 in mid-trimester. Miscarriage occurred in two cases in the early amniocentesis group (0.4%) and in ten cases among the mid-trimester group (0.3%). The overall loss of pregnancies due to amniocentesis in this study was 0.3%. Amniotic fluid was stained in 1.2% in the early group and 0.9% in the mid-trimester group. Amniotic fluid leakage was noted in 1.4% and 1.2%, preterm PROM was noted in 3.3%) and 3%, and preterm delivery occurred in 8% and 7.6%, respectively. There were no cases of failed amniotic culture and no cases of talipes equinovarous documented.

CONCLUSIONS

The risks of early amniocentesis performed between 13 + 0 and 14 + 6 weeks appear to be comparable to those of mid-trimester amniocentesis and thus early amniocentesis could be offered to the parents, as an alternative to chorionic villus sampling, in order to obtain cytogenetic results earlier in pregnancy without a significantly increased risk for both mother and fetus. Further operators' experience with the method, based on long and accurate follow-up, and further studies are necessary to assess the safety of the method.

S100B testing in pregnancy

Follow-up studies have shown that the vast majority of neurological abnormalities present during childhood can have a prenatal or perinatal origin. It is relevant, therefore, to investigate the timing of adverse insults in the search for measures of prevention. However, such knowledge is still incomplete and subject to debate. Until recently, clinical-laboratory assessment was based essentially on biochemical aspecific parameters, ultrasound and Doppler patterns, and the determination of blood pH and gases. However, the measurement of brain constituents may offer a direct indicator of cell damage in the nervous system. The S100B protein, a calcium-binding protein highly concentrated in the nervous system, appears to meet the criteria required of such a marker in prenatal and perinatal medicine for its reproducible, simple and sensible measurements. Results in high-risk pregnancies demonstrated that S100B concentration increased in amniotic fluid and in cord blood of fetuses with brain damage. In addition, S100B protein has been also usefully employed to monitor the effects of maternal-antenatal therapy, such as NO and glucocorticoid administration. It appears also to be relevant that a neurotrophic role has been hypothesized for the protein, which in fact exhibits in amniotic fluid, in cord blood and in placenta patterns of concentration related to the gestational age.

Thalassemia: current approach to an old disease

This article discusses the approach for recognition, diagnosis, and management of the thalassemias, and reviews new prospects of therapy, focusing mostly on the beta-thalassemias--the more severe and clinically important type, beta-thalassemia major is typically treated with regular transfusion and chelation therapy. New strategies for specific therapy including monitoring of iron induced organ damage, fetal hemoglobin augmentation as an alternative for transfusions, bone marrow transplantation offer hope for prevention of complications and better care of the beta-thalassemias.

Issues and concerns of couples presenting for preimplantation genetic diagnosis (PGD)

BACKGROUND

The use of preimplantation genetic diagnosis (PGD) to select genetically 'normal' human embryos and to transfer them to the uterus of a woman has generated considerable controversy. Debate has occurred over the implications of PGD, sex selection, safety of embryonic manipulation and eugenics. This study evaluates a range of social and moral concerns of couples towards PGD and assisted reproductive technologies (ART) prior to treatment to obtain unbiased authentic attitudes independent of the treatment cycle and the outcome.

METHODS

A total of 121 subjects were administered a structured questionnaire after each couple's in vitro fertilization (IVF) or genetic counselling session. Group A consisted of 41 subjects presenting for PGD of single gene disorders (PGD-SG) and group B consisted of 48 subjects undertaking PGD for aneuploidy screening (PGD-AS). A control group consisted of 32 subjects that were about to commence their first IVF cycle.

RESULTS AND DISCUSSION

All groups found PGD to be a highly acceptable treatment. They expressed little concern about its extension to testing non-disease states such as sex and they were strongly in favour of a shared decision-making model in which couples have considerable autonomy over decisions about the embryo(s) to transfer. Differences between the groups included issues surrounding the transfer of embryos, restrictions to PGD and the destruction of embryos.

Cystic fibrosis carrier testing in pregnancy in Canada

OBJECTIVE

To assess the role of cystic fibrosis (CF) testing within the Canadian health care environment.

METHODS

The Genetics and Maternal Fetal Medicine Committees of the Society of Obstetricians and Gynaecologists of Canada (SOGC) reviewed Preconception and Prenatal Carrier Screening for Cystic Fibrosis Clinical and Laboratory Guidelines produced by the American College of Obstetricians and Gynecologists (ACOG) and the American College of Medical Genetics (ACMG) and other educational material from ACOG and ACMG.

RESULTS

Background information related to cystic fibrosis, genetic mutation analysis, and one large clinical cystic fibrosis screening trial are reviewed.

EVIDENCE

The quality of evidence reported in this document has been described using the Evaluation of Evidence criteria outlined in the report of the Canadian Task Force on the Periodic Health Exam.

RECOMMENDATIONS

1. CF testing in pregnancy is indicated for individuals who may be at increased risk for CF due to considerations of family history or clinical manifestations. (II-2A). 2. Before CF screening could be undertaken, each province/territory would have to review the ethnic diversity of its reproductive population to ensure that CF screening would be appropriate. (III-C). 3. Screening of all women during pregnancy for CF carrier status cannot be recommended at this time. (III-C).

Prediction of fetal D status from maternal plasma: introduction of a new noninvasive fetal RHD genotyping service

BACKGROUND

Invasive procedures to obtain fetal DNA for prenatal blood grouping present a risk to the fetus. During pregnancy, cell-free fetal DNA is present in maternal blood. The detection of RHD sequences in maternal plasma has been used to predict fetal D status, based on the assumption that RHD is absent in D- genomes.

STUDY DESIGN AND METHODS

Real-time PCR assays were designed to distinguish RHD from RHDpsi (possessed by the majority of D- black Africans). Plasma-derived DNA from 137 D- women was subjected to real-time PCR to detect fetal RHD and Y chromosome-associated SRY sequences. The accuracy of RHD genotyping from maternal plasma was investigated by comparing results with those obtained by conventional RHD genotyping from fetal tissue or serologic tests on the infant's RBCs. The quantity of fetal DNA in maternal plasma was investigated in 94 pregnancies.

RESULTS

Fetal D status was predicted with 100-percent accuracy from maternal plasma. The number of copies of fetal DNA in maternal plasma was found to increase with gestation.

CONCLUSION

Combination of the sensitivity of real-time PCR with an improved RHD typing assay to distinguish RHD from RHDpsi enables highly accurate prediction of fetal D status from maternal plasma. This has resulted in the implementation of a clinical noninvasive fetal RHD genotyping service.

[Characteristics of pregnant women and routine antenatal care in Barcelona, 1994-1999]

OBJECTIVE

To analyse socio-demographic and pregnancy-control aspects of pregnant women residents in Barcelona city and their evolution during the period 1994-1999 using the controls of the Barcelona Birth Defects Registry.

METHODS

The information was collected by mean of an interview to the mother and from hospital records. The Mantel-Haenszel method for lineal association was used to analyse trends. A chi-squared test for proportions was used to compare pregnancy-control variables between public and private centers.

RESULTS

Data on 1,337 pregnant women were obtained. An increasing proportion of women older than 34 years is observed, from 19% in 1994-95 to 25% in 1998-99. An increase in the social class and a decrease of housewives is noticed. 40% of pregnancies were not planned and half of these finished in induced abortion. These proportions are higher in less than 25 and more than 39 years old mothers. 97% had their first obstetrical visit during the first trimester, almost all had at least an obstetrical ultrasound with a mean of 5.2, although 25% of the mothers did not undergo an ecography during the 5th month. An increase of invasive procedures and caesarean sections (C-section) is shown, with 33% of C-sections in the 98-99 period. The medical control of pregnancies is higher in mothers delivering in private centers, which are 55% of the total.

CONCLUSIONS

There is a high lack of pregnancy planning, as well as an increasing pregnancy medicalization, with positive (first trimester visit) and debatable aspects (obstetrical ultrasound, caesarean section and invasive procedures).