Maternal ethnicity and the prevalence of British pregnancies affected by neural tube defects

The potential impact of universal screening for vasa previa in the prevention of stillbirths

OBJECTIVES

To estimate the number of pregnancies complicated by vasa previa annually in nine developed countries, and the potential preventable stillbirths associated with undiagnosed cases. We also assessed the potential impact of universal screening for vasa previa on reducing stillbirth rates.

METHODS

We utilized nationally-reported birth and stillbirth data from public databases in the United States, United Kingdom, Canada, Germany, Ireland, Greece, Sweden, Portugal, and Australia. Using the annual number of births and the number and rate of stillbirths in each country, and the published incidence of vasa previa and stillbirth rates associated with the condition, we estimated the expected annual number of cases of vasa previa, those that would result in a livebirth, and the potential preventable stillbirths with and without prenatal diagnosis.

RESULTS

There were 6,099,118 total annual births with 32,550 stillbirths, corresponding to a summary stillbirth rate of 5.34 per 1,000 pregnancies. The total expected vasa previa cases was estimated to be 5,007 (95 % CI: 3,208-7,201). The estimated number of livebirths would be 4,937 (95 % CI: 3,163-7,100) and 3,610 (95 % CI: 2,313-5,192) in pregnancies with and without a prenatal diagnosis of VP. This implies that prenatal diagnosis would potentially prevent 1,327 (95 % CI: 850-1,908) stillbirths in these countries, corresponding to a potential reduction in stillbirth rate by 4.72 % (95 % CI: 3.80-5.74) if routine screening for vasa previa was performed.

CONCLUSIONS

Our study highlights the importance of universal screening for vasa previa and suggests that prenatal diagnosis of prevention could potentially reduce 4-5 % of stillbirths.

Tracking the Global Burden of Neural Tube Defects and Assessing Disparities Across World Health Organization Regions: A Scoping Literature Review

BACKGROUND AND OBJECTIVES

Neural tube defects (NTDs) are an important cause of global morbidity worldwide. Well-planned global neurosurgery and public health efforts can aid vulnerable communities, but there is a need to elucidate the global burden of NTDs and identify regions without available data to better target interventions.

METHODS

A scoping review to quantify worldwide NTD prevalence using the PubMed/Medline and birth defects surveillance registries was conducted. Data published after January 1, 1990, encompassing prevalence values of at least the 2 most prevalent NTDs-spina bifida and encephalocele-were abstracted. Average NTD prevalence rates were aggregated by World Health Organization (WHO) region and World Bank classification, and differences were determined using the analysis of variance test. Differences in availability of nationally representative data by WHO region and World Bank classification were determined using χ2 tests.

RESULTS

This review captured 140 studies from a total of 93 of 194 WHO member countries. The percentage of countries within a geographic region with available NTD prevalence data was highest in the Eastern Mediterranean (EMR) (85.7%) and lowest in Africa (AFR) (31.3%). The NTD prevalence range was 0.9-269.6 per 10 000 births. Statistically significant differences in reported NTD prevalence rates existed by WHO Region (P = .00027) and World Bank income level of study country (P = .00193). Forty countries (43%) had conducted national-level studies assessing NTD prevalence. There was a statistically significant difference in the availability of nationally representative prevalence data depending on the WHO region (P = .0081) and World Bank classification of study country (P = .0017).

CONCLUSION

There is a gap in availability of NTD prevalence data worldwide, with many WHO member states lacking national-level NTD prevalence estimates. These findings highlight the need for greater NTD surveillance efforts to identify the countries with the greatest need for targeted global intervention.

Use of 'stacked' dermal template: Biodegradable temporising matrix to close a large myelomeningocele defect in a newborn

Background

Myelomeningocele is a severe and complex congenital malformation of the central nervous system. Failure of neural tube closure at around four weeks of gestation results in an open communication between the neural placode and the external environment with varied functional impairment. Surgery is usually required.

Objectives

The primary goals of surgical management are to preserve neural function and minimise infection. Reconstruction is dependent upon the site and size of the defect as well as the quality of the surrounding soft tissues. Surgeons may employ a range of reconstructive techniques in order to achieve closure. Skin substitutes, also known as dermal regeneration templates, have also been utilised.

Discussion

In our unit, we use NovoSorb Biodegradable Temporising Matrix to reconstruct full-thickness skin and soft tissue defects. It is a synthetic, biodegradable, dermal regeneration template, composed of polyurethane foam bonded to a transparent sealing membrane and typically requires a two stage reconstruction. Integration and vascularisation take approximately three weeks. After this time, the recipient wound bed is suitable for split thickness skin grafting. A further benefit of dermal regeneration templates is the possibility of 'stacking' layers, which serves to increase the thickness of the final construct and to minimise overall contour defects. The authors present the case of a one-day-old full-term neonate with a large lumbosacral myelomeningocele that was successfully managed with staged, stacked NovoSorb Biodegradable Temporising Matrix and split thickness skin grafting. The authors believe this is the first case in which a 'stacked' dermal regeneration templates has been used to achieve healing of a primary myelomeningocele defect.

Lay Summary

Background: NovoSorb Biodegradable Temporising Matrix (BTM) is a dermal regeneration template (DRT) and is used to reconstruct wounds following full-thickness skin and soft tissue loss resulting from burn injury, trauma, infection or surgery. It is composed of 2-millimetre thick, synthetic, biodegradable polyurethane foam bonded to a transparent (non-biodegradable) sealing membrane. Like all DRTs, it acts as a scaffold for cellular integration and vascularisation to eventually form a 'neo-dermis'. This is usually apparent from around three weeks. A second stage procedure can then be performed, with removal of the outer sealing membrane and split thickness skin grafting of the vascularised layer.Objectives: Myelomeningocele is a severe and complex congenital malformation of the central nervous system and forms the group of anomalies commonly referred to as neural tube defects (NTDs). Neural tube closure usually occurs at around four weeks of gestation and failure to do so, results in an open communication between the neural placode and the external environment. The degree of functional impairment varies but can include: lower limb paralysis; sensory loss; bladder and bowel dysfunction. In order to preserve neural function and minimise the risk of infection, surgery is usually required to close the defect. Reconstruction is varied and is dependent upon the site and size of the defect as well as the quality of the surrounding soft tissues. The use of local flaps has the potential complication of skin necrosis. Muscle based flaps may be debilitating and limit future functionality and worsen postural development. We were presented with a one-day-old neonate with a large lumbosacral myelomeningocele. A DRT (NovoSorb BTM) was selected as the primary reconstruction. Firstly, selection provided relatively low risk, with minimal morbidity and preserved the full complement of flap based reconstructive options for a later stage should instrumentation be required. Secondly, NovoSorb BTM conferred a robust seal over the dural repair with no demonstrable cerebrospinal fluid leak. Thirdly, the ability to add layers ('stack') of NovoSorb BTM in stages, once integration and vascularisation of the previous layer is complete, allows reconstruction of deeper contour defects.Discussion: We have illustrated the successful use of NovoSorb BTM as a DRT to achieve closure of a large lumbosacral myelomeningocele without complication and with longstanding stability. We believe this technique provides reconstructive teams with an alternative option that is effective, safe and reproducible and which spares local tissues for future elective reconstructive procedures, should they be required.

Family experiences of antenatal counselling of spina bifida: a systematic review

OBJECTIVE

To describe families' experiences of antenatal counselling of spina bifida.

DESIGN

Systematic review.

METHODS

MEDLINE, CINAHL, PsycINFO and Embase databases were searched using a combination of Medical Subject Headings and text/abstract terms. Case reports, survey results and qualitative interview data were included. The quality of research was evaluated using the Critical Appraisal Skills Programme checklist.

RESULTS

8 papers were included. Families described shock and grief at diagnosis, with some immediately offered termination of pregnancy (TOP) even though they knew little about the condition. Positive and negative aspects of care were found. Teams that were gentle, kind and empathetic, who did not use jargon, and highlighted positive and negative aspects of the baby's life were seen favourably. Callous language, and overly negative or incorrect counselling was not, particularly if there was pressure to agree to TOP. Families based their decisions on how they would cope, the effect on siblings and the baby's likely quality of life. Prenatal surgery was viewed positively. The views of families who chose TOP, were happy with their care, partners, families, and the LGBTQ+ community were under-represented in the literature.

CONCLUSIONS

Unlike other conditions where limited data on outcome exist or the spectrum is genuinely broad, the outcomes of children with spina bifida is well described. Poor aspects of antenatal counselling were described frequently by families, and further work is needed to capture the full spectrum of views on antenatal counselling, how it can be improved, and what training and resources healthcare professionals need to perform it better.

A topographical analysis of encephalocele locations: generation of a standardised atlas and cluster analysis

OBJECTIVE

Encephaloceles are considered to result from defects in the developing skull through which meninges, and potentially brain tissue, herniate. The pathological mechanism underlying this process is incompletely understood. We aimed to describe the location of encephaloceles through the generation of a group atlas to determine whether they occur at random sites or clusters within distinct anatomical regions.

METHODS

Patients diagnosed with cranial encephaloceles or meningoceles were identified from a prospectively maintained database between 1984 and 2021. Images were transformed to atlas space using non-linear registration. The bone defect, encephalocele and herniated brain contents were manually segmented allowing for a 3-dimensional heat map of encephalocele locations to be generated. The centroids of the bone defects were clustered utilising a K-mean clustering machine learning algorithm in which the elbow method was used to identify the optimal number of clusters.

RESULTS

Of the 124 patients identified, 55 had volumetric imaging in the form of MRI (48/55) or CT (7/55) that could be used for atlas generation. Median encephalocele volume was 14,704 (IQR 3655-86,746) mm3 and the median surface area of the skull defect was 679 (IQR 374-765) mm2. Brain herniation into the encephalocele was found in 45% (25/55) with a median volume of 7433 (IQR 3123-14,237) mm3. Application of the elbow method revealed 3 discrete clusters: (1) anterior skull base (22%; 12/55), (2) parieto-occipital junction (45%; 25/55) and (3) peri-torcular (33%; 18/55). Cluster analysis revealed no correlation between the location of the encephalocele with gender (χ2 (2, n = 91) = 3.86, p = 0.15). Compared to expected population frequencies, encephaloceles were relatively more common in Black, Asian and Other compared to White ethnicities. A falcine sinus was identified in 51% (28/55) of cases. Falcine sinuses were more common (χ2 (2, n = 55) = 6.09, p = 0.05) whilst brain herniation was less common (χ2 (2, n = 55) = .16.24, p < 0.0003) in the parieto-occipital location.

CONCLUSION

This analysis revealed three predominant clusters for the location of encephaloceles, with the parieto-occipital junction being the most common. The stereotypic location of encephaloceles into anatomically distinct clusters and the coexistence of distinct venous malformations at certain sites suggests that their location is not random and raises the possibility of distinct pathogenic mechanisms unique to each of these regions.

Double whammy: the genetic variants in CECR2 and high Hcy on the development of neural tube defects

Introduction: Neural tube defects (NTDs) are serious congenital malformations. The etiology of NTDs involves both genetic and environmental factors. Loss of CECR2 in mice has been shown to result in NTDs. Our previous study indicated that high homocysteine (HHcy) levels could further reduced the expression level of CECR2. This investigation aims to explore the genetic influence of the chromatin remodeling gene, CECR2, in humans and determine if HHcy can have a synergistic effect on protein expression. Methods: We conducted Next-Generation Sequencing (NGS) of the CECR2 gene in 373 NTD cases and 222 healthy controls, followed by functional assay application to select and evaluate CECR2 missense variants and subsequent Western blotting to identify protein expression levels. Results: From the analysis, we identified nine rare, NTD-specific mutations within the CECR2 gene. Significantly, four missense variants (p.E327V, p.T521S, p.G701R, and p.G868R) were selected via functional screening. The E9.5 mouse ectodermal stem cell line NE-4C, transfected with plasmids expressing p.E327V, p.T521S, p.G868R variants or a recombinant harboring all four (named as 4Mut), exhibited notable reductions in CECR2 protein expression. Furthermore, exposure to homocysteine thiolactone (HTL), an extremely reactive homocysteine metabolite, amplified the reduction in CECR2 expression, accompanied by a significant increase in the apoptotic molecule Caspase3 activity, a potential NTD inducer. Importantly, folic acid (FA) supplementation effectively counteracted the CECR2 expression decline induced by CECR2 mutation and HTL treatment, leading to reduced apoptosis. Discussion: Our observations underscore a synergistic relationship between HHcy and genetic variations in CECR2 concerning NTDs, thereby reinforcing the concept of gene-environment interaction phenomena in NTD etiology.

Neural Tube Defects and Folate Deficiency: Is DNA Repair Defective?

Neural tube defects (NTDs) are complex congenital malformations resulting from failure of neural tube closure during embryogenesis, which is affected by the interaction of genetic and environmental factors. It is well known that folate deficiency increases the incidence of NTDs; however, the underlying mechanism remains unclear. Folate deficiency not only causes DNA hypomethylation, but also blocks the synthesis of 2'-deoxythymidine-5'-monophosphate (dTMP) and increases uracil misincorporation, resulting in genomic instabilities such as base mismatch, DNA breakage, and even chromosome aberration. DNA repair pathways are essential for ensuring normal DNA synthesis, genomic stability and integrity during embryonic neural development. Genomic instability or lack of DNA repair has been implicated in risk of development of NTDs. Here, we reviewed the relationship between folate deficiency, DNA repair pathways and NTDs so as to reveal the role and significance of DNA repair system in the pathogenesis of NTDs and better understand the pathogenesis of NTDs.

Global prevalence of congenital anencephaly: a comprehensive systematic review and meta-analysis

Background

Anencephaly is a fatal congenital anomaly characterized by the absence of brain hemispheres and cranial arch. Timely preventive measures can be taken by knowing the exact prevalence of this common neural tube defect; thus, carried out through systematic review and meta-analysis, the present study was conducted to determine the worldwide prevalence, incidence and mortality of anencephaly.

Methods

Cochran’s seven-step instructions were used as the guideline. Having determined the research question and inclusion and exclusion criteria, we studied MagIran, SID, Science Direct, WoS, Web of Science, Medline (PubMed), Scopus, and Google Scholar databases. Moreover, the search strategy in each database included using all possible keyword combinations with the help of “AND” and “OR” operators with no time limit to 2021. The I² test was used to calculate study heterogeneity, and Begg and Mazumdar rank correlation tests were employed to assess the publication bias. Data were analyzed by Comprehensive Meta-Analysis software (Version 2).

Results

In this study, the statements of Preferred Reporting Items for Systematic Reviews and Meta-Analyzes (PRISMA) were used. In the first stage, 1141 articles were found, of which 330 duplicate studies were omitted. 371 articles were deleted based on the inclusion and exclusion criteria by reviewing the title and abstract of the study. 58 articles were removed by reviewing the full text of the article because it was not relevant to the research. 360 studies with a sample size of 207,639,132 people were considered for the meta-analysis. Overall estimate of the prevalence, incidence and attenuation of anencephaly worldwide were 5.1 per ten thousand births (95% confidence interval 4.7–5.5 per ten thousand births), 8.3 per ten thousand births (95% confidence interval 5.5–9.9 per ten thousand births), 5.5 per ten thousand births (95% confidence interval 1.8–15 per ten thousand births) respectively the highest of which according to the subgroup analysis, belonged to the Australian continent with 8.6 per ten thousand births (95% confidence interval 7.7–9.5 per ten thousand births).

Conclusion

The overall prevalence of anencephaly in the world is significant, indicating the urgent need for preventive and treating measures.

Anencephaly is a fatal congenital anomaly characterized by the absence of brain hemispheres and cranial arch. Cochran’s seven-step instructions were used as the guideline. Having determined the research question and inclusion and exclusion criteria, we studied MagIran, SID, Science Direct, WoS, Web of Science, Medline (PubMed), Scopus, and Google Scholar databases. Moreover, the search strategy in each database included using all possible keyword combinations with the help of “AND” and “OR” operators with no time limit to 2021. Out of 1141 initial articles found, and after excluding repetitive ones in various databases and those irrelevant to inclusion criteria, 360 studies with a sample size of 207,639,132 people were considered for the meta-analysis. Overall estimate of the prevalence, incidence and attenuation of anencephaly worldwide were 5.1 per ten thousand births (95% confidence interval 4.7–5.5 per ten thousand births), 8.3 per ten thousand births (95% confidence interval 5.5–9.9 per ten thousand births), 5.5 per ten thousand births (95% confidence interval 1.8–15 per ten thousand births) respectively the highest of which according to the subgroup analysis, belonged to the Australian continent with 8.6 per ten thousand births (95% confidence interval 7.7–9.5 per ten thousand births). The overall prevalence of anencephaly in the world is significant, indicating the urgent need for preventive and treating measures.