A multidisciplinary and structured investigation of three suspected clusters of transverse upper limb reduction defects in France.

INTRODUCTION: Between 2019-2021, facing public concern, a scientific expert committee (SEC) reanalysed suspected clusters of transverse upper limb reduction defects (TULRD) in three administrative areas in France, where initial investigations had not identified any risk exposure. We share here the national approach we developed for managing suspicious clusters of the same group of congenital anomalies occurring in several areas. METHODS: The SEC analysed the medical records of TURLD suspected cases and performed spatiotemporal analyses on confirmed cases. If the cluster was statistically significant and included at least three cases, the SEC reviewed exposures obtained from questionnaires, environmental databases, and a survey among farmers living near to cases' homes concerning their plant product use. RESULTS: After case re-ascertainment, no statistically significant cluster was observed in the first administrative areas. In the second area, a cluster of four children born in two nearby towns over two years was confirmed, but as with the initial investigations, no exposure to a known risk factor explaining the number of cases in excess was identified. In the third area, a cluster including just two cases born the same year in the same town was confirmed. DISCUSSION: Our experience highlights that in the event of suspicious clusters occurring in different areas of a country, a coordinated and standardised approach should be preferred.

Clinical, genetic and biochemical signatures of RBP4-related ocular malformations.

BACKGROUND: The retinoic acid (RA) pathway plays a crucial role in both eye morphogenesis and the visual cycle. Individuals with monoallelic and biallelic pathogenic variants in retinol-binding protein 4 (RBP4), encoding a serum retinol-specific transporter, display variable ocular phenotypes. Although few families have been reported worldwide, recessive inherited variants appear to be associated with retinal degeneration, while individuals with dominantly inherited variants manifest ocular development anomalies, mainly microphthalmia, anophthalmia and coloboma (MAC). METHODS: We report here seven new families (13 patients) with isolated and syndromic MAC harbouring heterozygous RBP4 variants, of whom we performed biochemical analyses. RESULTS: For the first time, malformations that overlap the clinical spectrum of vitamin A deficiency are reported, providing a link with other RA disorders. Our data support two distinct phenotypes, depending on the nature and mode of inheritance of the variants: dominantly inherited, almost exclusively missense, associated with ocular malformations, in contrast to recessive, mainly truncating, associated with retinal degeneration. Moreover, we also confirm the skewed inheritance and impact of maternal RBP4 genotypes on phenotypical expression in dominant forms, suggesting that maternal RBP4 genetic status and content of diet during pregnancy may modify MAC occurrence and severity. Furthermore, we demonstrate that retinol-binding protein blood dosage in patients could provide a biological signature crucial for classifying RBP4 variants. Finally, we propose a novel hypothesis to explain the mechanisms underlying the observed genotype-phenotype correlations in RBP4 mutational spectrum. CONCLUSION: Dominant missense variants in RBP4 are associated with MAC of incomplete penetrance with maternal inheritance through a likely dominant-negative mechanism.

Familial transmission of chromoanagenesis leads to unpredictable unbalanced rearrangements through meiotic recombination.

Chromoanagenesis is a cellular mechanism that leads to complex chromosomal rearrangements (CCR) during a single catastrophic event. It may result in loss and/or gain of genetic material and may be responsible for various phenotypes. These rearrangements are usually sporadic. However, some familial cases have been reported. Here, we studied six families in whom an asymptomatic or paucisymptomatic parent transmitted a CCR to its offspring in an unbalanced manner. The rearrangements were characterized by karyotyping, fluorescent in situ hybridization, chromosomal microarray (CMA) and/or whole genome sequencing (WGS) in the carrier parents and offspring. We then hypothesized meiosis-pairing figures between normal and abnormal parental chromosomes that may have led to the formation of new unbalanced rearrangements through meiotic recombination. Our work indicates that chromoanagenesis might be associated with a normal phenotype and normal fertility, even in males, and that WGS may be the only way to identify these events when there is no imbalance. Subsequently, the CCR can be transmitted to the next generation in an unbalanced and unpredictable manner following meiotic recombination. Thereby, prenatal diagnosis using CMA should be proposed to these families to detect any pathogenic imbalances in the offspring.

Amniotic band syndrome and limb body wall complex in Europe 1980-2019.

Amniotic band syndrome (ABS) and limb body wall complex (LBWC) have an overlapping phenotype of multiple congenital anomalies and their etiology is unknown. We aimed to determine the prevalence of ABS and LBWC in Europe from 1980 to 2019 and to describe the spectrum of congenital anomalies. In addition, we investigated maternal age and multiple birth as possible risk factors for the occurrence of ABS and LBWC. We used data from the European surveillance of congenital anomalies (EUROCAT) network including data from 30 registries over 1980-2019. We included all pregnancy outcomes, including live births, stillbirths, and terminations of pregnancy for fetal anomalies. ABS and LBWC cases were extracted from the central EUROCAT database using coding information responses from the registries. In total, 866 ABS cases and 451 LBWC cases were included in this study. The mean prevalence was 0.53/10,000 births for ABS and 0.34/10,000 births for LBWC during the 40 years. Prevalence of both ABS and LBWC was lower in the 1980s and higher in the United Kingdom. Limb anomalies and neural tube defects were commonly seen in ABS, whereas in LBWC abdominal and thoracic wall defects and limb anomalies were most prevalent. Twinning was confirmed as a risk factor for both ABS and LBWC. This study includes the largest cohort of ABS and LBWC cases ever reported over a large time period using standardized EUROCAT data. Prevalence, clinical characteristics, and the phenotypic spectrum are described, and twinning is confirmed as a risk factor.

Epidemiology of aplasia cutis congenita: A population-based study in Europe.

BACKGROUND: Aplasia cutis congenita (ACC) is a rare congenital anomaly characterized by localized or widespread absence of skin at birth, mainly affecting the scalp. Most information about ACC exists as individual case reports and medium-sized studies. OBJECTIVES: This study aimed to investigate the epidemiology of ACC, using data from a large European network of population-based registries for congenital anomalies (EUROCAT). METHODS: Twenty-eight EUROCAT population-based registries in 16 European countries were involved. Poisson regression models were exploited to estimate the overall and live birth prevalence, to test time trends in prevalence between four 5-year periods and to evaluate the impact of the change of coding for ACC from the unspecific ICD9-BPA code to the specific ICD10 code. Proportions of ACC cases associated with other anomalies were reported. RESULTS: Five hundred cases were identified in the period 1998-2017 (prevalence: 5.10 per 100,000 births). Prevalence across 5-year periods did not differ significantly and no significant differences were evident due to the change from ICD9 to ICD10 in ACC coding. Heterogeneity in prevalence was observed across registries. The scalp was the most common site for ACC (96.4%) and associated congenital anomalies were present in 33.8% of cases. Patau and Adams-Oliver syndromes were the most frequent among the associated chromosomal anomalies (88.3%) and the associated genetic syndromes (57.7%), respectively. 16% of cases were associated with limb anomalies and 15.4% with congenital heart defects. A family history of ACC was found in 2% of cases. CONCLUSION: To our knowledge, this is the only population-based study on ACC. The EUROCAT methodologies provide reliable prevalence estimates and proportions of associated anomalies.

Epidemiology of Pierre-Robin sequence in Europe: A population-based EUROCAT study.

BACKGROUND: Pierre Robin sequence (PRS) is a rare congenital anomaly. Respiratory disorders and feeding difficulties represent the main burden. OBJECTIVE: The aim of this study was to investigate the epidemiology of PRS using a cohort of cases from EUROCAT, the European network of population-based registries of congenital anomalies. METHODS: We analysed cases of PRS born in the period 1998-2017 collected by 29 population-based congenital anomaly registries in 17 different countries. We calculated prevalence estimates, prenatal detection rate, survival up to 1 week, and proportions of associated anomalies. The effect of maternal age was tested using a Poisson regression model. RESULTS: Out of 11 669 155 surveyed births, a total of 1294 cases of PRS were identified. The estimate of the overall prevalence was 12.0 per 100 000 births (95% CI 9.9, 14.5). There was a total of 882 (68.2%) isolated cases, and the prevalence was 7.8 per 100 000 births (95% CI 6.7, 9.2). A total of 250 cases (19.3%) were associated with other structural congenital anomalies, 77 cases (6.0%) were associated with chromosomal anomalies and 77 (6.0%) with genetic syndromes. The prenatal detection rate in isolated cases was 12.0% (95% CI 9.8, 14.5) and increased to 16.0% (95% CI 12.7, 19.7) in the sub-period 2008-2017. The prevalence rate ratio of non-chromosomal cases with maternal age ≥35 was higher than in cases with maternal age <25 for total (PRR 1.26, 95% CI 1.05, 1.51) and isolated cases (PRR 1.33, 95% CI 1.00, 1.64). Survival of chromosomal cases (94.2%) and multiple anomaly cases (95.3%) were lower than survival of isolated cases (99.4%). CONCLUSIONS: This epidemiological study using a large series of cases of PRS provides insights into the epidemiological profile of PRS in Europe. We observed an association with higher maternal age, but further investigations are needed to test potential risk factors for PRS.

Spectrum of congenital anomalies among VACTERL cases: a EUROCAT population-based study.

BACKGROUND: The VACTERL (Vertebral anomalies, Anal atresia, Cardiac malformations, Tracheo-Esophageal fistula, Renal anomalies, Limb abnormalities) association is the non-random occurrence of at least three of these congenital anomalies: vertebral, anal, cardiac, tracheo-esophageal, renal, and limb anomalies. Diagnosing VACTERL patients is difficult, as many disorders have multiple features in common with VACTERL. The aims of this study were to clearly outline component features, describe the phenotypic spectrum among the largest group of VACTERL patients thus far reported, and to identify phenotypically similar subtypes. METHODS: A case-only study was performed assessing data on 501 cases recorded with VACTERL in the JRC-EUROCAT (Joint Research Centre-European Surveillance of Congenital Anomalies) central database (birth years: 1980-2015). We differentiated between major and minor VACTERL features and anomalies outside the VACTERL spectrum to create a clear definition of VACTERL. RESULTS: In total, 397 cases (79%) fulfilled our VACTERL diagnostic criteria. The most commonly observed major VACTERL features were anorectal malformations and esophageal atresia/tracheo-esophageal fistula (both occurring in 62% of VACTERL cases), followed by cardiac (57%), renal (51%), vertebral (33%), and limb anomalies (25%), in every possible combination. Three VACTERL subtypes were defined: STRICT-VACTERL, VACTERL-LIKE, and VACTERL-PLUS, based on severity and presence of additional congenital anomalies. CONCLUSION: The clearly defined VACTERL component features and the VACTERL subtypes introduced will improve both clinical practice and etiologic research.

Epidemiology of achondroplasia: A population-based study in Europe.

Achondroplasia is a rare genetic disorder resulting in short-limb skeletal dysplasia. We present the largest European population-based epidemiological study to date using data provided by the European Surveillance of Congenital Anomalies (EUROCAT) network. All cases of achondroplasia notified to 28 EUROCAT registries (1991-2015) were included in the study. Prevalence, birth outcomes, prenatal diagnosis, associated anomalies, and the impact of paternal and maternal age on de novo achondroplasia were presented. The study population consisted of 434 achondroplasia cases with a prevalence of 3.72 per 100,000 births (95%CIs: 3.14-4.39). There were 350 live births, 82 terminations of pregnancy after prenatal diagnosis, and two fetal deaths. The prenatal detection rate was significantly higher in recent years (71% in 2011-2015 vs. 36% in 1991-1995). Major associated congenital anomalies were present in 10% of cases. About 20% of cases were familial. After adjusting for maternal age, fathers >34 years had a significantly higher risk of having infants with de novo achondroplasia than younger fathers. Prevalence was stable over time, but regional differences were observed. All pregnancy outcomes were included in the prevalence estimate with 80.6% being live born. The study confirmed the increased risk for older fathers of having infants with de novo achondroplasia.

Epidemiology of Dandy-Walker Malformation in Europe: A EUROCAT Population-Based Registry Study.

BACKGROUND: Dandy-Walker (DW) malformation is a rare and severe congenital anomaly of the posterior fossa affecting the development of the cerebellum and the fourth ventricle. OBJECTIVE: The aim of this study was to investigate the epidemiology of DW malformation, using data from the European population-based registries of congenital anomalies in the European Surveillance of Congenital Anomalies network. METHODS: Anonymous individual data on cases of DW malformation diagnosed in 2002-2015 from 28 registries in 17 countries were included. Prevalence, prenatal detection rate, proportions and types of associated anomalies were estimated. Cases of DW variant were considered and analysed separately. RESULTS: Out of 8,028,454 surveyed births we identified a total of 734 cases, including 562 DW malformation cases and 172 DW variant cases. The overall prevalence of DW malformation was 6.79 per 100,000 births (95% CI 5.79-7.96) with 39.2% livebirths, 4.3% foetal deaths from 20 weeks gestational age, and 56.5% terminations of pregnancy after prenatal diagnosis of foetal anomaly at any gestation (TOPFA). The livebirth prevalence was 2.74 per 100,000 births (95% CI 2.08-3.61). The prenatal detection rate was 87.6%. Two-hundred and seventy-three cases (48.6%) had an isolated cerebral anomaly and 24.2, 19.2 and 5.5% cases were associated with other structural non-cerebral anomalies, chromosomal anomalies and genetic syndromes respectively. The prevalence of DW variant was 2.08 per 100,000 (95% CI 1.39-3.13). CONCLUSIONS: This European population-based study provides the epidemiological profile of DW malformation. All birth outcomes were analysed and TOPFA represented more than half of the cases. About 50% of the cases of DW malformation were associated with other non-cerebral anomalies. Large populations and all birth outcomes are essential in epidemiological studies of rare and severe congenital anomalies.

Impact of prenatal diagnosis on the outcome of patients with a transposition of great arteries: A 24-year population-based study.

BACKGROUND: Transposition of great arteries (TGA) defined as the combination of concordant atrioventricular and discordant ventriculo-arterial connections is one of the most common congenital heart defects. Prenatal diagnosis of TGA remains difficult. To determine the impact of antenatal diagnosis we evaluated the sensitivity of antenatal detection and the neonatal mortality of TGA considering two study periods and two major types of TGA. METHODS: A cross-sectional study was performed. Data were collected from a French population-based birth defect registry. From 1988 to 2012, 94 fetuses with TGA were registered. The study period was subdivided into the 1988 to 1999 period and the 2000 to 2012 period. Two types of TGA were considered: isolated TGA (n = 66) and associated TGA (n = 28). A stratified analysis was performed considering the study periods and the types of TGA. RESULTS: Considering the study periods, the sensitivity of prenatal detection of TGA increased significantly (9.8% vs. 51.5%, p = 0.0001). The same trend was found for associated TGA (4.8% vs. 33.3%, p = 0.002) and isolated TGA (21.1% vs. 100%, p < 0.001). A late diagnosis of TGA (7 days after birth) was observed in 13.2% of cases. Neonatal mortality decreased significantly over time for isolated TGA (25.0% vs. 0 p = 0.01). Prenatal diagnosis of both types of TGA did not improve survival. CONCLUSION: We demonstrated that prenatal diagnosis and neonatal mortality of TGA varied greatly according to the malformation type and the study period. This could be explained by an improvement in terms of medical management.

Prenatal diagnosis of the VACTERL association using routine ultrasound examination.

BACKGROUND: The prognosis and early neonatal management of the VACTERL association depend mainly on the severity of malformations ascertained prenatally. METHODS: Here we reviewed the spectrum of clinical features observed in cases of VACTERL association ascertained prenatally through ultrasound examination but examined at birth and compared them with cases ascertained postnatally. RESULTS: From 1995 to 2011, a total of 19 cases of VACTERL association were observed in our center; 10 were ascertained prenatally and confirmed after birth whereas 9 were ascertained only after birth. The types and frequencies of malformations observed prenatally were as follows: renal malformations (45%), tracheoesophageal fistula (44%), cardiac malformations (20%), vertebral (13%), and limb (11%) defects. Anal atresia was never detected using routine prenatal ultrasound examination. CONCLUSION: Further studies of fetuses with the VACTERL association are necessary to better delineate the malformations spectrum observed prenatally to improve the early recognition of the VACTERL association.

False positive morphologic diagnoses at the anomaly scan: marginal or real problem, a population-based cohort study.

BACKGROUND: Congenital malformations occur in 3-4% of live births. Their prenatal detection is performed by ultrasound screening. Any announcement about a suspected malformation is a source of stress for the parents, and misdiagnosis during ultrasound screening can lead to expensive and sometimes iatrogenic medical interventions. In this study, we aim to determine the false-positive rate, first overall and then by anatomical system, of ultrasound screening for congenital malformations in the second and third trimesters of pregnancy. METHODS: Our sample includes all children born between 1 January, 2006, and 31 December, 2009, in the French region of Auvergne, whose mother had a prenatal ultrasound diagnosis of a congenital malformation during the second or third trimester of pregnancy confirmed by a follow-up ultrasound examination by an expert consultant ultrasonographer. The study included 526 fetuses, divided in 3 groups: false positives, diagnostic misclassifications, and true positives. The rates of false positives and diagnostic misclassifications were calculated for the sample as a whole and then by anatomical system. RESULTS: Overall, the false-positive rate was 8.8% and the rate of diagnostic misclassification 9.2%. The highest false-positive rates were found for renal and gastrointestinal tract malformations, and the highest diagnostic misclassification rates for cerebral and cardiac malformations. The diagnostic misclassification rate was significantly higher than the false-positive rate for cardiac malformations. CONCLUSION: The false-positive rate during prenatal ultrasound is not insignificant; these misdiagnoses cause psychological stress for the parents and overmedicalisation of the pregnancy and the child.

Surveillance of multiple congenital anomalies; searching for new associations.

Many human teratogens are associated with a spectrum of congenital anomalies rather than a single defect, and therefore the identification of congenital anomalies occurring together more frequently than expected may improve the detection of teratogens. Thirty-two EUROCAT congenital anomaly registries covering 6,599,765 births provided 123,566 cases with one or more major congenital anomalies (excluding chromosomal and genetic syndromes) for the birth years 2008-2016. The EUROCAT multiple congenital anomaly algorithm identified 8804 cases with two or more major congenital anomalies in different organ systems, that were not recognized as part of a syndrome or sequence. For each pair of anomalies, the odds of a case having both anomalies relative to having only one anomaly was calculated and the p value was estimated using a two-sided Fisher's exact test. The Benjamini-Hochberg procedure adjusted p values to control the false discovery rate and pairs of anomalies with adjusted p values < 0.05 were identified. A total of 1386 combinations of two anomalies were analyzed. Out of the 31 statistically significant positive associations identified, 20 were found to be known associations or sequences already described in the literature and 11 were considered "potential new associations" by the EUROCAT Coding and Classification Committee. After a review of the literature and a detailed examination of the individual cases with the anomaly pairs, six pairs remained classified as new associations. In summary, systematically searching for congenital anomalies occurring together more frequently than expected using the EUROCAT database is worthwhile and has identified six new associations that merit further investigation.

Performance map of a cluster detection test using extended power.

BACKGROUND: Conventional power studies possess limited ability to assess the performance of cluster detection tests. In particular, they cannot evaluate the accuracy of the cluster location, which is essential in such assessments. Furthermore, they usually estimate power for one or a few particular alternative hypotheses and thus cannot assess performance over an entire region. Takahashi and Tango developed the concept of extended power that indicates both the rate of null hypothesis rejection and the accuracy of the cluster location. We propose a systematic assessment method, using here extended power, to produce a map showing the performance of cluster detection tests over an entire region. METHODS: To explore the behavior of a cluster detection test on identical cluster types at any possible location, we successively applied four different spatial and epidemiological parameters. These parameters determined four cluster collections, each covering the entire study region. We simulated 1,000 datasets for each cluster and analyzed them with Kulldorff's spatial scan statistic. From the area under the extended power curve, we constructed a map for each parameter set showing the performance of the test across the entire region. RESULTS: Consistent with previous studies, the performance of the spatial scan statistic increased with the baseline incidence of disease, the size of the at-risk population and the strength of the cluster (i.e., the relative risk). Performance was heterogeneous, however, even for very similar clusters (i.e., similar with respect to the aforementioned factors), suggesting the influence of other factors. CONCLUSIONS: The area under the extended power curve is a single measure of performance and, although needing further exploration, it is suitable to conduct a systematic spatial evaluation of performance. The performance map we propose enables epidemiologists to assess cluster detection tests across an entire study region.

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.

Maternal age and the prevalence of congenital heart defects in Europe, 1995-2015: A register-based study.

BACKGROUND: Evidence on the direction and strength of association between maternal age and the prevalence of congenital heart defects (CHD) in different age group categories is conflicting. Some studies have illustrated different trends with an increase in prevalence in younger and older age groups while other studies have reported a linear relationship. Given the increase in maternal age over recent years, it is important to study the CHD prevalence by maternal age. OBJECTIVES: To examine the association between maternal age and the prevalence of CHD in Europe between 1995 and 2015 using population-based data from 24 registries belonging to the European Surveillance of Congenital Anomalies (EUROCAT) network. METHODS: Associations over time of all nonsyndromic CHD according to maternal age category and for three CHD severity groupings (severity group I: very severe; severity group II: severe; severity group III: less severe) were examined using Bayesian multilevel Poisson regression modeling. Further subgroup analyses were undertaken within four maternal age-bands: ≤24, 25-29, 30-34 and 35-44 years. Descriptive summaries are also presented. RESULTS: There were 51,608 nonsyndromic CHD cases in Europe over the 20-year study period. Total prevalence for all CHD combined was increased for younger mothers (≤24 years) and for mothers 35-44 years of age when compared with mothers aged 25-29 years (reference group) (IRR: 1.05, 95% CI: 1.02, 1.07). The total prevalence was increased for severity group I (very severe) only for younger mothers compared to those aged 25-29 years (IRR: 1.14, 95% CI: 1.04, 1.23). We found an increased prevalence of the following CHD subtypes: double outlet right ventricle (IRR:1.33, 95% CI: 1.09, 1.60), hypoplastic left heart syndrome (IRR: 1.18, 95% CI: 1.05, 1.32), hypoplastic right heart syndrome (IRR: 1.41, 95% CI: 1.05, 1.84), atrioventricular septal defect (IRR: 1.15, 95% CI: 1.01, 1.32), coarctation of aorta (IRR: 1.15, 95% CI: 1.03, 1.28) and atrial septal defect (IRR: 1.08, 95% CI: 1.02, 1.13). For older mothers (35-44 years) compared to the reference category, we observed an increased risk in the prevalence for severity group II (IRR: 1.09, 95% CI: 1.03, 1.14), severity group III (IRR: 1.05, 95% CI: 1.01, 1.08) and an increased prevalence of the CHD subtypes: Pulmonary valve stenosis (IRR: 1.22, 95% CI: 1.09, 1.34), ASD (IRR: 1.07, 95% CI: 1.02, 1.13), CoA (IRR: 1.18, 95% CI: 1.06, 1.32) and Tetralogy of Fallot (IRR: 1.14, 95% CI: 1.01, 1.28). Finally, for all age categories compared to the reference category, different associations of ASD and an increased prevalence of CoA was also observed. CONCLUSIONS: Based on data for cases of CHD from 24 European population-based registries, evidence of a positive association between maternal age and the total prevalence of CHD for younger (≤24 years old) and older (35-44 years old) mothers was observed. The results suggest that young maternal age (≤24 years old) is a factor associated with severe CHD phenotypes while a positive association between advanced maternal age (35-44 years old) and mild CHD phenotypes was observed.

Identification of the First Single GSDME Exon 8 Structural Variants Associated with Autosomal Dominant Hearing Loss.

GSDME, also known as DFNA5, is a gene implicated in autosomal dominant nonsyndromic hearing loss (ADNSHL), affecting, at first, the high frequencies with a subsequent progression over all frequencies. To date, all the GSDME pathogenic variants associated with deafness lead to skipping of exon 8. In two families with apparent ADNSHL, massively parallel sequencing (MPS) integrating a coverage-based method for detection of copy number variations (CNVs) was applied, and it identified the first two causal GSDME structural variants affecting exon 8. The deleterious impact of the c.991-60_1095del variant, which includes the acceptor splice site sequence of exon 8, was confirmed by the study of the proband's transcripts. The second mutational event is a complex rearrangement that deletes almost all of the exon 8 sequence. This study increases the mutational spectrum of the GSDME gene and highlights the crucial importance of MPS data for the detection of GSDME exon 8 deletions, even though the identification of a causal single-exon CNV by MPS analysis is still challenging.

Prevalence of congenital heart defects in Europe, 2008-2015: A registry-based study.

BACKGROUND: The total prevalence of congenital heart defects (CHDs) varies by populations and over time. Studies that examine trends in the prevalence of CHD in different regions may shed light on our understanding of the occurrence of CHD and the impact of different risk factors. OBJECTIVES: To examine trends in total and live birth prevalence of nonsyndromic CHD in Europe between the years 2008 and 2015 and to investigate if the decreasing trend reported by previous studies is continuing. METHODS: Cases of CHD delivered between January 1, 2008 and December 31, 2015 notified to 25 population-based EUROCAT (European Surveillance of Congenital Anomalies) registries in 14 countries, formed the population-based case-series. Prevalence (total/live) rates and 95% confidence intervals were calculated as the number of cases per 10,000 births (live and stillbirths). Time trends in prevalence of all nonsyndromic CHDs and for three CHD severity groups (very severe, severe, and less severe) were plotted using a Poisson regression multilevel approach. RESULTS: The total prevalence of nonsyndromic CHD was 57.1 per 10,000 births (live births and stillbirths) for the 8-year period and remained stable across the three CHD severity groups while the live birth prevalence was 60.2 per 10,000 births. There was considerable variation in the reported total CHD prevalence and the direction of trends by registry. A decreasing prevalence of CHD was observed for the Norway and England/Wales registries, whereas the CHD prevalence increased for registries in Italy and Croatia. CONCLUSIONS: The total prevalence of CHD in Europe between the years 2008 and 2015 remained stable for all CHD and across the three CHD severity groups. The decreasing trend reported by previous studies has not continued. However, we found significant differences in the total and live birth prevalence by registry.

Prevalence of vascular disruption anomalies and association with young maternal age: A EUROCAT study to compare the United Kingdom with other European countries.

BACKGROUND: Younger mothers are at a greater risk of having a pregnancy with gastroschisis and the risk is higher in the United Kingdom than other European countries. Gastroschisis is thought to be a vascular disruption anomaly and the aim of this study was to analyze the prevalence of other possible vascular disruption anomalies to determine whether both the younger maternal age and the UK associations also occur with these anomalies. METHODS: All pregnancies with anomalies considered potentially due to vascular disruption from January 1, 2005 to December 31, 2017 from 26 European population-based congenital anomaly registries who were members of EUROCAT were analyzed. Multilevel models were used to allow for differences between registries when analyzing associations with maternal age, year of birth and whether the registry was in the United Kingdom. RESULTS: There were 5,220 cases with potential vascular disruption anomalies, excluding chromosomal and genetic conditions, with a prevalence of 8.85 per 10,000 births in the United Kingdom and 5.44 in the other European countries. The prevalence per 10,000 births of gastroschisis (4.45 vs. 1.56) and congenital constriction bands (0.83 vs. 0.42) was significantly higher in the United Kingdom, even after adjusting for maternal age. However, transverse limb reduction defects had a similar prevalence (2.16 vs. 2.14 per 10,000). The expected increased prevalence in younger mothers was observed for vascular disruption anomalies overall and for the individual anomalies: gastroschisis and congenital constriction bands. CONCLUSION: Vascular disruption anomalies that had an increased risk for younger mothers (such as gastroschisis) had a higher maternal age standardized prevalence in the United Kingdom, while vascular disruption anomalies with weaker associations with younger mothers (such as transverse limb reduction defects) did not have an increased prevalence in the United Kingdom, which may indicate a different etiology for these anomalies.