Etiological diagnosis in limb reduction defects and the number of affected limbs: A population-based study in the Northern Netherlands

Prevalence, infant outcomes and gestational risk factors for transverse reduction deficiencies at or above the wrist: a population-based study

We identified individuals born in Norway between 1970 and 2019 with transverse reduction deficiency at or above the wrist (TRDAW) from the Medical Birth Registry of Norway and from the CULA (congenital upper limb anomaly) North Oslo Registry. Infant outcomes and parental factors were compared for 202 individuals with TRDAW to 2,741,013 living individuals without TRDAW born during the same period. We found an overall TRDAW prevalence of 0.74/10,000. Infants with TRDAW had a higher risk for being small for gestational age, an Apgar score <7 and transfer to neonatal intensive care units after delivery. Nine of the infants with TRDAW had associated anomalies, most commonly in the lower limb, and at a higher proportion than the reference population. Other than twin pregnancies, we are unable to identify with certainty any other risk factors for TRDAW.Level of evidence: I.

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.

Tracheal agenesis versus tracheal atresia: anatomical conditions, pathomechanisms and causes with a possible link to a novel MAPK11 variant in one case

BACKGROUND

In this study we aimed to describe the morphological and pathogenetic differences between tracheal agenesis and tracheal atresia, which are not clearly distinguished from each other in the literature, and to contribute thereby to the understanding and management of these conditions. Both tracheal agenesis and tracheal atresia represent rare disorders of still unknown aetiology that cannot be detected by prenatal ultrasound. If the affected foetuses survive until birth these conditions result in respiratory failure and in futile attempts to rescue the infant's life.

RESULTS

Autopsies and genetic analyses, including singleton or trio exome sequencing, were performed on five neonates/foetuses with tracheal agenesis and three foetuses with tracheal atresia. Tracheal agenesis was characterized by absence of the sublaryngeal trachea and presence of a bronchooesophageal fistula and by pulmonary isomerism and occurred as an isolated malformation complex or as part of a VACTERL association. Special findings were an additional so-called 'pig bronchus' and a first case of tracheal agenesis with sirenomelia. Tracheal atresia presenting with partial obliteration of its lumen and persistence of a fibromuscular streak resulted in CHAOS. This condition was associated with normal lung lobulation and single, non-VACTERL type malformations. Trio ES revealed a novel variant of MAPK11 in one tracheal agenesis case. Its involvement in tracheooesophageal malformation is herein discussed, but remains hypothetical.

CONCLUSION

Tracheal agenesis and tracheal atresia represent different disease entities in terms of morphology, pathogenesis and accompanying anomalies due to a primary developmental and secondary disruptive possibly vascular disturbance, respectively.

Updated EUROCAT guidelines for classification of cases with congenital anomalies

BACKGROUND

Precise and correct classification of congenital anomalies is important in epidemiological studies, not only to classify according to etiology but also to group similar congenital anomalies together, to create homogeneous subgroups for surveillance and research. This paper presents the updated EUROCAT (European surveillance of congenital anomalies) subgroups of congenital anomalies and the updated multiple congenital anomaly (MCA) algorithm and provides the underlying arguments for the revisions.

METHODS

The EUROCAT methodology is described. In addition, we show how we validated the revised EUROCAT subgroups and MCA algorithm, which are both based on the International Classification of Diseases (ICD10/ICD9) codes.

RESULTS

The updated EUROCAT subgroups and the updated MCA algorithm are described in detail and the updated version is compared to the previous versions.

CONCLUSION

The EUROCAT subgroups and MCA algorithm provide a standardized and clear methodology for congenital anomaly research and epidemiological surveillance of congenital anomalies in order to facilitate the identification of teratogenic exposures and to assess the impact of primary prevention and prenatal screening policies. The EUROCAT subgroups and MCA algorithm are made freely available for other researchers via the EUROCAT Database Management Software.

Congenital Limb Defects: A Retrospective Cohort Study and Overview of the Literature

PURPOSE

Congenital limb defects are common malformations that are often associated with other organ defects and genetic disorders. Since prenatal detection is challenging and classification is often complex, the aim of this study was to describe a large cohort of fetuses with congenital limb defects and to identify characteristics that are essential for prenatal evaluation, counselling, and management.

MATERIALS AND METHODS

In this retrospective cohort study, all cases of confirmed fetal limb defects from two centers for prenatal ultrasound between 2001 and 2021 were evaluated. Cases with skeletal dysplasia were excluded from this study. Demographic data, association with genetic disorders, and correlation with maternal parameters were analyzed statistically.

RESULTS

170 fetuses were included in this study. 60% were diagnosed with a reduction anomaly and 40% with a duplication anomaly. The majority of fetuses were male, and in 73.5% of all cases, additional malformations were present. Among the genetic causes, trisomy 13 and 18 were the most common in this cohort.

CONCLUSION

Congenital limb malformations are important markers for complex fetal disorders that warrant referral to specialists in prenatal ultrasound. To improve prenatal detection, care should be taken to visualize all fetal extremities already in early pregnancy.

Maternal Cigarette Smoking and Congenital Upper and Lower Limb Differences: A Systematic Review and Meta-Analysis

Maternal smoking during pregnancy has been associated with adverse effects on foetal development, including congenital limb anomalies. This systematic review aimed to provide an updated assessment of the association between maternal smoking during pregnancy and the risk of congenital limb anomalies. A systematic search was conducted to identify relevant studies published up to February 2023. Studies reporting on the relationship between maternal smoking during pregnancy and congenital digital anomalies or congenital limb reduction defects were included. Two independent reviewers screened the studies, extracted data, and assessed the quality of the included studies. Meta-analyses were performed to estimate the pooled odds ratios with 95% confidence intervals using fixed and random-effects models. In total, 37 publications comprising 11 cohort and 26 case-control studies were included in the systematic review. The meta-analysis demonstrated a significant increased risk of congenital limb reduction defects (pooled OR: 1.27, 95% CI: 1.18-1.38) in infants born to mothers who smoked during pregnancy. Similarly, a significant relationship was observed for the development of polydactyly/syndactyly/adactyly when considered as a single group (pooled OR: 1.32, 95% CI: 1.25-1.40). Yet, in contrast, no significant association was observed when polydactyly (pooled OR: 1.06, 95% CI: 0.88-1.27) or syndactyly (pooled OR: 0.91, 95% CI: 0.77-1.08) were considered individually. This systematic review provides updated evidence of a significant relationship between maternal smoking during pregnancy and increased risk of congenital limb anomalies. These findings highlight the potential detrimental effects of smoking on foetal limb development and underscore the importance of smoking cessation interventions for pregnant women to mitigate these risks.

Prenatal radiographic evaluation of congenital transverse limb deficiencies: A scoping review

BACKGROUND

Congenital transverse deficiencies are horizontal deficiencies of the long bones that occur with a reported incidence as high 0.38%. They can occur alone or represent a manifestation of a various clinical syndromes. Diagnosis has traditionally comprised of conventional radiography and prenatal imaging studies. There has been much advancement regarding prenatal imaging modalities to allow for early diagnosis and appropriate treatment.

AIM

To summarize the current state of knowledge on congenital transverse limb deficiencies and to provide an update regarding the radiographic evaluation of congenital transverse limb deficiencies.

METHODS

This IRB-exempt scoping review followed the PRISMA-ScR checklist for scoping reviews strictly. Five search engines were searched for a total of 265 publications. Four authors reviewed these during the screening process. Of these, 51 studies were included in our article. Prenatal magnetic resonance imaging (MRI), 3D Ultrasound, and multidetector Computed tomography (CT) exist are emerging modalities that have the potential to improve diagnosis.

RESULTS

Use of the appropriate classification system, three-dimensional ultrasonography with a maximum intensity projection, and appropriate use of prenatal MRI and prenatal CT can improve diagnosis and inter-provider communication.

CONCLUSION

Further scholarly efforts are required to develop improve standardized guidelines regarding the pre-natal radiographic evaluation of congenital limb deficiencies.

Fetal Hands: A Comprehensive Review of Prenatal Assessment and Diagnosis Over the Past 40 Years

Fetal skeletal dysplasias involving limbs and hands are rare congenital malformations. Prenatal two-dimensional ultrasound diagnosis of fetal limb defects has a sensitivity of about 30%; however, an increased detection rate may be obtained using three-dimensional (3-D) ultrasound in the rendering mode. 3-D ultrasound may be used as a complementary method providing additional information. Currently, magnetic resonance imaging (MRI), with the emergence of ultrafast imaging techniques and new sequences, allows for better diagnosis of several fetal skeletal dysplasias such as limb reduction defects and neuromuscular disorders. 3-D volumetric images from ultrasound or MRI scan data allow 3-D ultrasound reconstructions of virtual/physical models, and virtual reality can help researchers to improve our understanding of both normal and abnormal fetal limb/hand anatomy. In this article, we review the embryological development of fetal hands and their main anomalies including prenatal diagnostic methods, genetic counseling, the role of orthopedic and plastic surgery reconstruction, and new perspectives in fetal surgery.

The Alberta Congenital Anomalies Surveillance System: a 40-year review with prevalence and trends for selected congenital anomalies, 1997-2019

INTRODUCTION

Current published long-term provincial or territorial congenital anomaly data are lacking for Canada. We report on prevalence (per 1000 total births) and trends in 1997-2019, in Alberta, Canada, for selected congenital anomalies. Associated risk factors are also discussed.

METHODS

We used data from the Alberta Congenital Anomalies Surveillance System (ACASS) to calculate the prevalence and perform chi-square linear trend analyses.

RESULTS

From 1997 to 2019, the overall prevalence of neural tube defects was stable, at 0.74 per 1000 total births. The same was true for spina bifida (0.38), orofacial clefts (1.99), more severe CHDs (transposition of the great arteries, 0.38; tetralogy of Fallot, 0.33; and hypoplastic left heart syndrome, 0.32); and gastroschisis (0.38). Anencephaly, cleft palate and anorectal malformation significantly decreased with a prevalence of 0.23, 0.75 and 0.54 per 1000 total births, respectively. Significantly increasing trends were reported for anotia/microtia (0.24), limb reduction anomalies (0.73), omphalocele (0.36) and Down syndrome (2.21) and for hypospadias and undescended testes (4.68 and 5.29, respectively, per 1000 male births).

CONCLUSION

Congenital anomalies are an important public health concern with significant social and societal costs. Surveillance data gathered by ACASS for over 40 years can be used for planning and policy decisions and the evaluation of prevention strategies. Contributing genetic and environmental factors are discussed as is the need for continued surveillance and research.

Spectrum of fetal limb anomalies

PURPOSE

Antenatal detection of limb anomalies is not uncommon, and pregnancies are usually terminated in view of the expected physical handicap. The aim of this retrospective observational study is to delineate the spectrum of fetal limb anomalies and provide evidence in support of complete postnatal evaluation in establishing recurrence risk.

METHODS

We present 54 cases of limb malformations detected antenatally and discuss the spectrum of abnormalities, the utility of fetal autopsy, and genetic testing to establish recurrence risk in subsequent pregnancies.

RESULTS

16/54 cases were isolated radial ray anomalies. There were five cases of amniotic band syndrome, five limb body wall complex cases, three VACTERL (vertebral defects, anal atresia, cardiac defects, tracheo-esophageal fistula, renal anomalies, and limb abnormalities) associations, one case of sirenomelia, two cases of limb pelvis hypoplasia, and one case of OEIS (Omphalocele Exstrophy Imperforate anus and spinal defects). Four fetuses with non-isolated radial ray anomaly had trisomy 18. One case with bilateral radial ray defect had a mutation in the FANC-E gene confirming fanconi anemia. Twelve cases were unclassified.

CONCLUSION

Autopsy is the most important investigation in fetuses with limb anomalies. We suggest chromosomal microarray (CMA) as a first-tier test after autopsy. However, in cases of bilaterally symmetrical limb anomalies, in case of previous similarly affected child, or history of consanguinity, whole exome sequencing (WES) can be offered as the primary investigation, followed by CMA if WES is normal.

Prenatal diagnosis and pregnancy outcome of major structural anomalies detectable in the first trimester: A population-based cohort study in the Netherlands

BACKGROUND

Prenatal diagnosis of several major congenital anomalies can be achieved in the first trimester of pregnancy.

OBJECTIVE

This study investigates the timing of diagnosis and pregnancy outcome of foetuses and neonates with selected structural anomalies in the Northern Netherlands over a 10-year period when the prenatal screening programme changed significantly, but no first-trimester anatomical screening was implemented.

METHODS

We performed a population-based retrospective cohort study with data from the EUROCAT Northern Netherlands database on pregnancies with delivery or termination of pregnancy for fetal anomaly (TOPFA) date between 2010 and 2019. The analysis was restricted to anomalies potentially detectable in the first trimester of pregnancy in at least 50% of cases, based on previously published data. These included: anencephaly, encephalocele, spina bifida, holoprosencephaly, tricuspid/pulmonary valve atresia, hypoplastic left heart, abdominal wall and limb reduction defects, lethal skeletal dysplasia, megacystis, multiple congenital anomalies. The primary outcome was the timing of diagnosis of each structural anomaly. Information on additional investigations, genetic testing and pregnancy outcome (live birth, TOPFA and foetal/neonatal death) was also collected.

RESULTS

A total of 478 foetuses were included; 95.0% (n = 454) of anomalies were detected prenatally and 5.0% (n = 24) postpartum. Among the prenatally detected cases, 31% (n = 141) were diagnosed before 14 weeks of gestation, 65.6% (n = 298) between 14-22 weeks and 3.3% (n = 15) after 22 weeks. Prenatal genetic testing was performed in 80.4% (n = 365) of cases with prenatally diagnosed anomalies, and the results were abnormal in 26% (n = 95). Twenty-one% (n = 102) of pregnancies resulted in live births and 62.8% (n = 300) in TOPFA. Spontaneous death occurred in 15.9% (n = 76) of cases: in-utero (6.1%, n = 29), at delivery (7.7%, n = 37) or in neonatal life (2.1%, n = 10).

CONCLUSION

Major structural anomalies amenable to early diagnosis in the first trimester of pregnancy are mostly diagnosed during the second trimester in the absence of a regulated first-trimester anatomical screening programme in the Netherlands and are associated with TOPFA and spontaneous death, especially in cases with underlying genetic anomalies.

Congenital limb deficiency: Genetic investigation of 44 individuals presenting mainly longitudinal defects in isolated or syndromic forms

Congenital limb deficiency (CLD), one of the most common congenital anomalies, is characterized by hypoplasia/aplasia of one or more limb bones and can be isolated or syndromic. The etiology in CLD is heterogeneous, including environmental and genetic factors. A fraction remains with no etiological factor identified. We report the study of 44 Brazilian individuals presenting isolated or syndromic CLD, mainly with longitudinal defects. Genetic investigation included particularly next-generation sequencing (NGS) and/or chromosomal microarray. The overall diagnostic yield was 45.7%, ranging from 60.9% in the syndromic to 16.7% in the non-syndromic group. In TAR syndrome, a common variant in 3´UTR of RBM8A, in trans with 1q21.1 microdeletion, was detected, corroborating the importance of this recently reported variant in individuals of African ancestry. NGS established a diagnosis in three individuals in syndromes recently reported or still under delineation (an acrofacial dysostosis, Coats plus and Verheij syndromes), suggesting a broader phenotypic spectrum in these disorders. Although a low rate of molecular detection in non-syndromic forms was observed, it is still possible that variants in non-coding regions and small CNVs, not detected by the techniques applied in this study, could play a role in the etiology of CLD.

Maternal Risk Factors Associated with Limb Reduction Defects: Data from the Polish Registry of Congenital Malformations (PRCM)

Data from the Polish Registry of Congenital Malformations (PRCM) suggest that the prevalence of limb reduction defects (LRDs) in some Polish regions is significantly higher in comparison to that reported in the European Surveillance of Congenital Anomalies (EUROCAT) registry, but specific risk factors are still unknown. The objectives of this study were two-fold: to detect risk factors linked to isolated LRDs among Polish natives and to search for geospatial clusters of isolated LRDs to identify high-risk areas across the country. Among the 2,939,001 births accounted for in the PRCM, we determined that there were 852 children with distinct LRDs. Our data demonstrate that lower birth weight, prematurity, and maternal smoking history are strongly associated with isolated LRDs. Furthermore, our investigation pointed to various additional risk factors for isolated LRDs, including paternal education, gestational hypertension, upper respiratory tract infections, and exposure to anti-inflammatory drugs in the first trimester of pregnancy. We did not recognize statistically significant spatial or spatiotemporal clusters over the area of Poland using Kulldorff’s scan. Our study strengthens the hypothesis that maternal factors have an integral role in the etiology of isolated LRDs.

Evidence for a cluster of rare birth defects in the Ain department (France)

BACKGROUND

REMERA (REgistre des Malformations En Rhône-Alpes) is a registry of congenital malformations that covers 58,000 births annually in Central-East France. In 2010, the registry raised an alarm to the health authorities (Santé publique France, SpF) about three cases of a unilateral isolated transverse upper limb reduction defect (UITULRD) in a small subarea; the general prevalence of this defect is one case in 10,000 births. In the following years, more infants were born with the same malformation in the same territory of the Ain department. Public health authorities, supported by an expert committee, rejected the existence of a cluster, but we aim here at providing evidence for this cluster.

METHODS

Geocoded data for all UITULRD cases (ICD-10 codes Q71.2 and Q71.3) were extracted from the REMERA database. We conducted a Kulldorff cluster analysis of these data, using the spatial SaTScanTM algorithm.

RESULTS

The analysis found a cluster of eight cases of UITULRD among the 8,204 births occurring between 2009 and 2014 within a circle of 16.24 km radius centered on a village of the Ain department, whereas 0.82 cases were expected under a uniform probability of such a birth throughout the registry territory. This represents an almost 10fold excess over the expected number of cases (p = .0057).

CONCLUSIONS

The arguments used to deny the cluster are disputed and we present the evidence supporting its reality. The controversy that has followed the alarm has compromised the search for the cause(s) of this excess of rare malformations.

Etiological diagnosis in limb reduction defects and the number of affected limbs: A population-based study in the Northern Netherlands

Limb reduction defects (LRDs) that affect multiple limbs are considered to be more often heritable, but only few studies have substantiated this. We aimed to investigate if an etiological diagnosis (genetic disorder or clinically recognizable disorder) is more likely to be made when multiple limbs are affected compared to when only one limb is affected. We used data from EUROCAT Northern Netherlands and included 391 fetuses and children with LRDs born in 1981–2017. Cases were classified as having a transverse, longitudinal (preaxial/postaxial/central/mixed), intercalary, or complex LRD of one or more limbs and as having an isolated LRD or multiple congenital anomalies (MCA). We calculated the probability of obtaining an etiological diagnosis in cases with multiple affected limbs versus one affected limb using relative risk (RR) scores and Fisher's exact test. We showed that an etiological diagnosis was made three times more often when an LRD occurred in multiple limbs compared to when it occurred in one limb (RR 2.9, 95% CI 2.2–3.8, p < 0.001). No genetic disorders were found in isolated cases with only one affected limb, whereas a genetic disorder was identified in 16% of MCA cases with one affected limb. A clinically recognizable disorder was found in 47% of MCA cases with one affected limb. Genetic counseling rates were similar. We conclude that reduction defects of multiple limbs are indeed more often heritable. Genetic testing seems less useful in isolated cases with one affected limb, but is warranted in MCA cases with one affected limb.