Reduced telomere length in amniocytes: an early biomarker of abnormal fetal development?

Telomeres protect chromosome ends and control cell division and senescence. During organogenesis, telomeres need to be long enough to ensure the cell proliferation necessary at this stage of development. Previous studies have shown that telomere shortening is associated with growth retardation and congenital malformations. However, these studies were performed in newborns or postnatally, and data on telomere length (TL) during the prenatal period are still very limited. We measured TL using quantitative PCR in amniotic fluid (AF) and chorionic villi (CV) samples from 69 control fetuses with normal ultrasound (52 AF and 17 CV) and 213 fetuses (165 AF and 48 CV) with intrauterine growth retardation (IUGR) or congenital malformations diagnosed by ultrasound. The samples were collected by amniocentesis at the gestational age (GA) of 25.0 ± 5.4 weeks and by CV biopsy at 18.1 ± 6.3 weeks. In neither sample type was TL influenced by GA or fetal sex. In AF, a comparison of abnormal versus normal fetuses showed a significant telomere shortening in cases of IUGR (reduction of 34%, P < 10-6), single (29%, P < 10-6) and multiple (44%, P < 10-6) malformations. Similar TL shortening was also observed in CV from abnormal fetuses but to a lesser extent (25%, P = 0.0002; 18%, P = 0.016; 20%, P = 0.004, respectively). Telomere shortening was more pronounced in cases of multiple congenital anomalies than in fetuses with a single malformation, suggesting a correlation between TL and the severity of fetal phenotype. Thus, TL measurement in fetal samples during pregnancy could provide a novel predictive marker of pathological development.

Severe neuromuscular forms of glycogen storage disease type IV: Histological, clinical, biochemical, and molecular findings in a large French case series.

Glycogen storage disease type IV (GSD IV), also called Andersen disease, or amylopectinosis, is a highly heterogeneous autosomal recessive disorder caused by a glycogen branching enzyme (GBE, 1,4-alpha-glucan branching enzyme) deficiency secondary to pathogenic variants on GBE1 gene. The incidence is evaluated to 1:600 000 to 1:800 000 of live births. GBE deficiency leads to an excessive deposition of structurally abnormal, amylopectin-like glycogen in affected tissues (liver, skeletal muscle, heart, nervous system, etc.). Diagnosis is often guided by histological findings and confirmed by GBE activity deficiency and molecular studies. Severe neuromuscular forms of GSD IV are very rare and of disastrous prognosis. Identification and characterization of these forms are important for genetic counseling for further pregnancies. Here we describe clinical, histological, enzymatic, and molecular findings of 10 cases from 8 families, the largest case series reported so far, of severe neuromuscular forms of GSD IV along with a literature review. Main antenatal features are: fetal akinesia deformation sequence or arthrogryposis/joint contractures often associated with muscle atrophy, decreased fetal movement, cystic hygroma, and/or hydrops fetalis. If pregnancy is carried to term, the main clinical features observed at birth are severe hypotonia and/or muscle atrophy, with the need for mechanical ventilation, cardiomyopathy, retrognathism, and arthrogryposis. All our patients were stillborn or died within 1 month of life. In addition, we identified five novel GBE1 variants.

Safety and Immunogenicity of an Investigational Respiratory Syncytial Virus Vaccine (RSVPreF3) in Mothers and Their Infants: A Phase 2 Randomized Trial.

BACKGROUND: In a phase 1/2 study, a maternal respiratory syncytial virus vaccine candidate (RSVPreF3) demonstrated an acceptable safety profile and efficiently increased RSV-specific humoral immune responses in non-pregnant women. METHODS: In this phase 2 observer-blind, placebo-controlled, randomized clinical trial (NCT04126213), the safety of RSVPreF3 (60 or 120 µg), administered during late second or third trimester, was evaluated in 213 18- to 40-year-old healthy pregnant women through 6 months postdelivery and their offspring through infancy; immunogenicity was evaluated through day 43 postdelivery and day 181 postbirth, respectively. RESULTS: RSVPreF3 was well tolerated. No pregnancy-related or neonatal adverse events of special interest were considered vaccine/placebo related. In the 60 and 120 µg RSVPreF3 groups: (1) neutralizing antibody (nAb) titers in mothers increased 12.7- and 14.9-fold against RSV-A and 10.6- and 13.2-fold against RSV-B, respectively, 1 month postvaccination and remained 8.9-10.0-fold over prevaccination at day 43 postdelivery; (2) nAb titers were consistently higher compared to placebo recipients; (3) placental transfer ratios for anti-RSVPreF3 antibodies at birth were 1.62 and 1.90, respectively, and (4) nAb levels in infants were highest at birth and declined through day 181 postbirth. CONCLUSIONS: RSVPreF3 maternal vaccination had an acceptable safety risk profile and induced robust RSV-specific immune responses with successful antibody transfer to their newborns. CLINICAL TRIALS REGISTRATION: NCT04126213.

WHAT IS THE CONTEXT?: Infants, especially those less than 6 months of age, are at increased risk of lung infection caused by respiratory syncytial virus (RSV). However, this risk could be reduced with maternal vaccination against RSV during pregnancy. A previous clinical trial found that a vaccine candidate (named RSVPreF3) was well tolerated when given to non-pregnant women. WHAT IS NEW?: In pregnant women, RSVPreF3 was also well tolerated. Occurrence of unsolicited adverse events was similar between vaccine and placebo recipients. None of the serious adverse events or events of interest for pregnant women or newborns were considered related to the study intervention. One month after vaccination, mothers who received RSVPreF3 had 11­15 times higher levels of antibodies against RSV than before vaccination. These antibody levels remained similar until 43 days after delivery. In the infants born to mothers vaccinated during pregnancy with RSVPreF3, antibody levels were highest at birth, when levels were higher than in their mothers, and declined through day 181 postbirth. WHAT IS THE IMPACT?: RSVPreF3 had an acceptable safety risk profile in pregnant women and their babies. This vaccine induced potent immune responses against RSV, with maternal antibodies transferred to infants of the vaccinated mothers.

The Pubic Diastasis Measurement, a Key Element for the Diagnosis, Management, and Prognosis of the Bladder Exstrophy.

OBJECTIVE: To demonstrate the feasibility of measuring the fetal pubic diastasis (PD) distance on antenatal ultrasound in normal fetuses and to compare it to fetuses with bladder exstrophy. METHODS: Firstly, a prospective multicentric study was conducted to determine the feasibility of the PD ultrasound measurement during the second half of pregnancy. Secondly, data from a single center were used to develop a nomogram for PD values in normal fetuses. Thirdly, retrospective PD measurements were collected from fetuses with bladder exstrophy, diagnosed in seven French Multidisciplinary Centers for Prenatal Diagnosis (MCPDs). RESULTS: Operators from several MCPDs examined 868 fetuses and found that overall PD ultrasound measurement was feasible in 71% of cases and that the ossification of pubic points increased to be always visible from 27 weeks of gestation onward. Performed in a single center by a referring operator on 1,539 fetuses, the feasibility reached 94.74%. Both set of measurements were concordant (mean PD distance value of 5.42 ± 1.8 mm). Interestingly, all 23 fetuses with bladder exstrophy showed a significantly larger PD distance (mean 15.74 ± 3.9 mm). CONCLUSION: PD measurement in the fetus is feasible and reliable in the second half of gestation and can be used to support the antenatal diagnosis of bladder exstrophy with PD values exceeding 10 mm.

A novel 2q14.1q14.3 deletion involving GLI2 and RNU4ATAC genes associated with partial corpus callosum agenesis and severe intrauterine growth retardation.

BACKGROUND: Microdeletions encompassing chromosome bands 2q14.1q14.3 are rare. To date, eight reports of relatively large deletions of this region (∼20 Mb) but only two small deletions (<6 Mb) have been reported. These deletions can cause a variable phenotype depending on the size and location of the deletion. Cognitive disability, facial dysmorphism, and postnatal growth retardation are the most common phenotypic features. CASE: We report on a novel 5.8 Mb deletion of 2q14.1q14.3 identified by array comparative genomic hybridization in a fetus with severe intrauterine growth retardation and partial agenesis of the corpus callosum. The deletion contained 24 coding genes including STEAP3, GLI2, and RNU4ATAC and was inherited from the mild affected mother. A sibling developmental delay and similar dysmorphic facial features was found to have inherited the same deletion. CONCLUSION: This case emphasizes the variable expressivity of the 2q14 microdeletion and reinforces the hypothesis that agenesis of corpus callosum, microcephaly, developmental delay, and distinctive craniofacial features may be part of the phenotypic spectrum characterizing the affected patients. We suggest that GLI2 is a dosage-sensitive gene that may be responsible for the agenesis of corpus callosum observed in the proband. Birth Defects Research (Part A) 106:793-797, 2016. © 2016 Wiley Periodicals, Inc.

Feasibility of Optical Genome Mapping from Placental and Umbilical Cord Sampled after Spontaneous or Therapeutic Pregnancy Termination.

Optical genome mapping (OGM) is an alternative to classical cytogenetic techniques to improve the detection rate of clinically significant genomic abnormalities. The isolation of high-molecular-weight (HMW) DNA is critical for a successful OGM analysis. HMW DNA quality depends on tissue type, sample size, and storage conditions. We assessed the feasibility of OGM analysis of DNA from nine umbilical cord (UC) and six chorionic villus (CV) samples collected after the spontaneous or therapeutic termination of pregnancy. We analyzed quality control metrics provided by the Saphyr system (Bionano Genomics) and assessed the length of extracted DNA molecules using pulsed-field capillary electrophoresis. OMG data were successfully analyzed for all six CV samples. Five of the UC samples did not meet the Saphyr quality criteria, mainly due to poor DNA quality. In this regard, we found that DNA quality assessment with pulsed-field capillary electrophoresis can predict a successful OGM analysis. OGM data were fully concordant with the results of standard cytogenetic methods. Moreover, OGM detected an average of 14 additional structural variants involving OMIM genes per sample. On the basis of our results, we established the optimal conditions for sample storage and preparation required for a successful OGM analysis. We recommend checking DNA quality before analysis with pulsed-field capillary electrophoresis if the storage conditions were not ideal or if the quality of the sample is poor. OGM can therefore be performed on fetal tissue harvested after the termination of pregnancy, which opens up the perspective for improved diagnostic yield.

Optical genome mapping for prenatal diagnosis: A prospective study.

PURPOSE: Cytogenetic analysis provides important information for prenatal decision-making and genetic counseling. Optical genome mapping (OGM) has demonstrated its performances in retrospective studies. In our prospective study, we assessed the quality of DNA obtained from cultures of amniotic fluid (AF) and chorionic villi (CV) and evaluated the ability of OGM to detect all clinically relevant aberrations identified by standard methods. METHODS: A total of 37 prenatal samples from pregnancies with a fetal anomaly on ultrasound were analyzed prospectively by OGM between January 1, 2021 and June 31, 2022. OGM results were interpreted blindly and compared to the results obtained by standard techniques. RESULTS: OGM results were interpretable in 92% of samples. We observed 100% concordance between OGM and karyotype and/or chromosomal microarray results. In addition, OGM identified a median of 30 small (<100 kb) structural variations per case with the involvement of 12 OMIM genes, of which 3 were OMIM morbid genes. CONCLUSION: This prospective study showed OGM performed well in detecting genomic alterations in cell cultures from prenatal samples. The place of OGM in relation to CMA or exome sequencing remains to be defined in order to optimize the prenatal diagnostic procedure.

Cost-effectiveness threshold of first-trimester Down syndrome maternal serum screening for the use of cell-free DNA as a second-tier screening test.

INTRODUCTION: We aimed to identify the most relevant cost-effectiveness threshold of first-trimester Down syndrome (DS) maternal serum screening (T21T1) for the use of cell-free DNA (cfDNA) as a second-tier test in the French context. METHOD: A cost-effectiveness analysis was performed on 108,121 singleton pregnancies using a simulation model. The threshold of T21T1 screening was ranged from 1/51 to 1/1,000 in steps of 1/50. The most relevant threshold was based on cost-effectiveness ratio (CER; costs = direct medical costs after T21T1 screening/ effectiveness = number of DS cases identified). RESULTS: In the sample, 161 cases of DS were identified. At the threshold of ≥ 1/50, 47.2% of total DS cases were diagnosed. In the simulation model, for a threshold ≥ 1/250, 73.9% of total DS cases were diagnosed, for ≥ 1/500, 78.8% and for ≥ 1/1,000, only two additional cases were diagnosed. The slope of the cost increase was slight from threshold ≥ 1/250 (978,634 €), then steep up to 1/500 (1,966,576 €) and increased exponentially to 1/1,000 (3,980,216 €). The CER was 38,560 for a threshold ≥ 1/500. CONCLUSION: The most cost-effective threshold for cfDNA as a second-tier test seems to be ≥ 1/500. For higher thresholds, costs increase dramatically for only a few additional cases of DS identified.

Hyperechoic congenital lung lesions in a non-selected population: from prenatal detection till perinatal management.

OBJECTIVE: To present longitudinal observations of hyperechoic lung lesions (HLL) in a non-selected population from the time of prenatal diagnosis by ultrasound (US) until postnatal surgery. METHODS: We conducted a retrospective study of all fetuses diagnosed with an HLL between 1990 and 2005 in our Fetal Medicine Unit. RESULTS: We observed 21 cases of HLL. Among the 17 fetuses with unilateral lesion, two cyst punctures were attempted on fetuses with signs of fetal compromise. Termination of pregnancy (TOP) was performed on seven fetuses. Fourteen fetuses were followed till birth. First Chest X-ray was abnormal in ten cases, while delayed CT scans revealed a lung lesion in 12 cases. Two neonates required emergency surgery and died post operatively. Surgery was successfully performed in all other cases (n = 10). Pathological examination revealed congenital high airway obstruction syndrome, CHAOS (n = 4), lower airway stenosis (n = 2), bronchogenic cyst (n = 1), congenital lobar emphysema (n = 1), and congenital cystic adenomatoid malformation, CCAM (n = 11) including two cases associated with a sequestration. CONCLUSION: HLL cover a wide spectrum of lung abnormalities of various severities. Post natal management should always include an early chest X-ray and CT scan to allow appropriate selection for surgery.

Antenatal detection and impact on outcome of congenital diaphragmatic hernia: a 12-year experience in Auvergne, France.

OBJECTIVE: To evaluate the detection rate of prenatal diagnosis and its impact on outcome in congenital diaphragmatic hernia (CDH). STUDY DESIGN: We retrospectively studied 51 cases of CDH registered in the Auvergne area from January 1992 to December 2003 (Birth Defect Registry of Auvergne, Institut Européen des Génomutations). Our main outcome measurements were the detection rate of prenatal diagnosis, the incidence and types of associated anomalies and outcome (termination of pregnancy, in utero fetal demise, neonatal death, survival at the time of registration). RESULTS: Twenty-nine cases of isolated CDH were identified of which 13 were detected prenatally (45%) at a mean gestational age of 26.1 weeks and 22 cases of CDH with associated anomalies with prenatal diagnosis of CDH or any associated anomaly in 16 (73%; p=0.03) at a mean gestational age of 23.9 weeks. In the prenatally detected group (29 cases), there was 1 (3%) in utero fetal death (IUFD), 17 (59%) terminations of pregnancy (TOP) and 11 (38%) live births with early neonatal death in 7 (24%) cases despite delivery in a tertiary care centre in 10/11 cases (four survivors=14%). Most of the undetected cases were isolated CDH (16/22=73%) of which 1 (5%) was a stillborn and 21 (95%) live births with 17 survivors (77%) although 15/21 (71%) were not born at the tertiary care centre (p=0.001). The overall survival rate was 41% with a large variability depending on associated anomalies and prenatal diagnosis (p<0.0001) (prenatally detected cases: 3/13 (23%) isolated CDH and 1/16 (6%) CDH with associated anomalies; undetected cases: 13/16 (81%) isolated CDH and 4/6 (67%) CDH with associated anomalies). CONCLUSION: Prenatal diagnosis of CDH leads to the delivery of affected babies in tertiary care centres but it remains a challenge in particular for isolated CDH cases and it is associated with a lower survival rate. Associated anomalies contribute to prenatal detection, are related to a higher TOP rate but do not facilitate the detection of diaphragmatic defect per se.

Congenital diaphragmatic hernia: a retinoid-signaling pathway disruption during lung development?

Congenital diaphragmatic hernia (CDH) usually occurs sporadically. The prognosis remains poor, with a 50% perinatal mortality rate. Most deaths result from hypoxemia due to lung hypoplasia and abnormal development of pulmonary vasculature that results in persistent pulmonary hypertension. Our current understanding of the pathogenesis of CDH is based on an assumption linking herniation of abdominal viscera into the thorax with compression of the developing lung. Pulmonary hypoplasia, however, can also result from reduced distension of the developing lung secondary to impaired fetal breathing movements. Moreover, a nitrofen-induced CDH model shows that lung hypoplasia precedes the diaphragmatic defect, leading to a "dual-hit hypothesis." Recent data reveal the role of a retinoid-signaling pathway disruption in the pathogenesis of CDH. We describe the clinical and epidemiological aspects of human CDH, the metabolic and molecular aspects of the retinoid-signaling pathway, and the implications of retinoids in the development of the diaphragm and the lung. Finally, we highlight the existing links between CDH and disruption of the retinoid-signaling pathway, which may suggest an eventual use of retinoids in the treatment of CDH.

Experience with three cases of laparoscopic transabdominal cervico-isthmic cerclage and two subsequent pregnancies.

Three women with a history of recurrent miscarriages and failed vaginal cerclage had laparoscopic transabdominal cerclage. A 5 mm non-absorbable polyether suture was placed laparoscopically at the level of the internal os as an interval procedure. All procedures were successful. All women were discharged on day 2 and none required transfusion. Two of them were pregnant within four months and were delivered by caesarean section at 38 weeks of gestation. The main interest of this technique is to avoid a laparotomy; thus, reducing the abdominal wall aggression and the recovery time.

Chorionic villus sampling (CVS) and fluorescence in situ hybridization (FISH) for a rapid first-trimester prenatal diagnosis.

OBJECTIVES: Early diagnosis of unbalanced chromosomal abnormalities can be crucial in minimizing the trauma caused by an elective abortion. Chorionic villus sampling (CVS) can be performed from 9 weeks of gestation. However, two major problems are encountered in fetal karyotyping using cultured cells from chorionic villi: the relatively slow growth of these cells in culture, which delays the diagnosis, and the occurrence of maternal cell contamination (MCC). With FISH, a result can be obtained within 24 h, and, as no cell culturing is involved, the problem of MCC is minimized. METHODS: Thirty-two women undergoing CVS between 9 and 12 weeks of gestation were offered FISH analysis in addition to the standard chromosome analysis. RESULTS: FISH was informative in all of the cases tested. Eleven aneuploidies were detected in cases of hygroma or abnormal nuchal translucency and two out of four fetuses from parental translocation were unbalanced. The decision to perform early termination of these chromosomally abnormal pregnancies was based on FISH results and ultrasound abnormalities, without waiting for karyotype results. CONCLUSION: The present study confirms that the association of FISH and CVS allows a rapid and early prenatal diagnosis, and emphasizes that this association is of great benefit in cases of known parental balanced translocation or when hygroma is detected by ultrasonography.