Describing the Prevalence of Neural Tube Defects Worldwide: A Systematic Literature Review

Surgical Outcomes after Myelomeningocele Repair in Lusaka, Zambia

OBJECTIVE

Spina bifida disproportionally affects low-and-middle-income countries. We describe myelomeningocele surgical outcomes in Zambia and predictors of postoperative complications and mortality.

METHODS

This 2-center retrospective cohort study includes children who underwent surgical treatment for myelomeningocele in Lusaka, Zambia from 2017 to 2019. Primary outcomes included mortality and 30-day postoperative complications.

RESULTS

Seventy-five patients were identified. Median age at first neurosurgical evaluation was 9 days (interquartile range [IQR], 6-21) and at surgery was 21 days (IQR 15-36). Lumbosacral myelomeningocele was most common (73%, n = 54). At first preoperative evaluation, 28% of the neural tube defects were deemed infected (n = 21), and 30% were leaking cerebrospinal fluid (n = 21). Postoperatively, 7% of patients died (n = 5), whereas 31% experienced a complication (n = 23). Most common complications included wound dehiscence (n = 10, 42%) and wound purulence (n = 6, 25%). Median follow-up duration was 41 days (IQR, 6-128). On univariable analysis, mortality was significantly associated with shorter follow-up duration (5 days [IQR, 2-7] vs. 46 days [IQR, 12-132]; P = 0.02) and any complication (P < 0.001). No variable was significantly associated with postoperative complication; however, 2 variables that notably neared significance were preoperative infection of the lesion (P = 0.05) and longer surgical delay (P = 0.06).

CONCLUSIONS

Most patients born with myelomeningocele in Zambia present for first neurosurgical evaluation after 1 week of age. Preoperative infection of the lesion and postoperative complications are relatively common, and complications are a significant predictor of postoperative mortality. Further investigation into preoperative efforts to mitigate risk of postoperative complications and mortality is warranted.

Association of paternal smoking with the risk of neural tube defects in offspring: A systematic review and meta-analysis of observational studies

PURPOSE

The present study aimed at providing some epidemiological evidences to assess the association of paternal smoking with the risk of neural tube defects (NTDs) and its specific subtypes in offspring, and explore the possible dose-response relationship between paternal smoking and risk of NTDs.

METHODS

English and Chinese databases were systematically searched from 1984 to May 2020. Either a fixed- or a random-effects model was used to calculate the overall combined risk estimates. We also examined the dose-response relationship between parental smoking and risk of NTDs in offspring. Subgroup analyses and sensitivity analyses were conducted to explore possible sources of heterogeneity.

RESULTS

A total of 10 case-control studies involving 2,593 cases of NTDs and 45,100 controls were included for analysis. Findings from our study showed that paternal smoking was significantly associated with risk of total NTDs (odds ratio [OR] = 1.68; 95% confidence interval (CI): 1.48-1.92) and two subtypes including anencephaly (OR = 1.41; 95% CI: 1.06-1.86) and encephaloceles (OR = 2.90; 95% CI: 1.00-8.41). Additionally, a linear dose-response relationship between paternal smoking and risk of NTDs was observed, which indicated that the risk of NTDs in offspring was significantly increased by 45% (OR = 1.45, 95% CI: 1.14-1.84) for each increment of half a pack of cigarettes per day. Sensitivity analyses yielded consistent results. No evidence of publication bias was found.

CONCLUSIONS

Paternal smoking is significantly associated with the risk of NTDs in offspring. Therefore, it should be recommended that fathers quit smoking before pregnancy to prevent NTDs in offspring.

Imaging findings in association with altered maternal alpha-fetoprotein levels during pregnancy

Maternal serum alpha-fetoprotein is a valuable laboratory test used in pregnant women as an indicator to detect certain clinical abnormalities. These can be grouped into four main categories: fetal factors, pregnancy complications, placental abnormalities, and maternal factors. Imaging is an invaluable tool to investigate the various etiologies leading to altered maternal serum alpha-fetoprotein. By reading this article, the radiologist, sonologist, or other health care practitioner should be able to define the probable pathology leading to the laboratory detected abnormal maternal serum levels, thus helping the clinician to appropriately manage the pregnancy and counsel the patient.

Safety and efficacy of supplements in pregnancy

Pregnancy is a time where expectant mothers often focus on their diet to improve their own health and to preserve the future health of their children. There is much conflicting information in the public domain about the safety and/or efficacy of nutritional supplements during pregnancy. Despite this, the market for supplements is growing. This review discusses the roles of critical nutrients in pregnancy and the available evidence on the use of supplements to reduce risks and improve maternal and fetal outcomes. Recommendations are made for pregnant women, taking into account safety data and tolerable upper intakes set for pregnant women. It is important for dieticians, nutritionists, physicians, and other healthcare providers to be able to offer accurate and evidence-based advice on supplement use in pregnancy. Routine supplementation may not be necessary for all, but individuals at risk are identified.

Engineered tissues and strategies to overcome challenges in drug development

Current preclinical studies in drug development utilize high-throughput in vitro screens to identify drug leads, followed by both in vitro and in vivo models to predict lead candidates' pharmacokinetic and pharmacodynamic properties. The goal of these studies is to reduce the number of lead drug candidates down to the most likely to succeed in later human clinical trials. However, only 1 in 10 drug candidates that emerge from preclinical studies will succeed and become an approved therapeutic. Lack of efficacy or undetected toxicity represents roughly 75% of the causes for these failures, despite these parameters being the primary exclusion criteria in preclinical studies. Recently, advances in both biology and engineering have created new tools for constructing new preclinical models. These models can complement those used in current preclinical studies by helping to create more realistic representations of human tissues in vitro and in vivo. In this review, we describe current preclinical models to identify their value and limitations and then discuss select areas of research where improvements in preclinical models are particularly needed to advance drug development. Following this, we discuss design considerations for constructing preclinical models and then highlight recent advances in these efforts. Taken together, we aim to review the advances as of 2020 surrounding the prospect of biological and engineering tools for adding enhanced biological relevance to preclinical studies to aid in the challenges of failed drug candidates and the burden this poses on the drug development enterprise and thus healthcare.

Population-level assessment of atlas occipitalization in artificially modified crania from pre-Hispanic Peru

Atlas occipitalization (AO) is a spinal anomaly, characterized by the fusion of the first cervical vertebra and occipital bone, with a complex etiology that can arise from congenital and environmental causes. AO has been reported in three regions of pre-Hispanic Peru in skeletal remains with artificial cranial modification (ACM), which involves the use of compression devices to permanently alter cranial shape and may have affected the fusion of the atlas and occipital bone. The aims of this study were to gain insights into AO’s etiology by testing correlations between AO and ACM presence/type and geographic region as well as to characterize morphological variation associated with AO. We investigated the geographic distribution of AO and its potential relationship to ACM in a large sample of human crania from eight coastal and highland regions of pre-Hispanic Peru, held at the Smithsonian’s National Museum of Natural History (n = 608, 1300–1500 CE). Eleven cases of AO were observed in three coastal regions—including two previously unreported regions—at an overall frequency of 1.8%. The frequency of AO did not differ significantly between crania with and without ACM, in general or by type, suggesting that ACM is not an etiological factor that influences AO in this sample. AO was observed at a significantly higher rate in the southern coastal region of Arequipa than in any other region. Genetic, dietary, and epidemiological conditions are evaluated as factors possibly shaping the geographic distribution of AO along the central and southern coasts of Peru.

Burden of rare deleterious variants in WNT signaling genes among 511 myelomeningocele patients

Genes in the noncanonical WNT signaling pathway controlling planar cell polarity have been linked to the neural tube defect myelomeningocele. We hypothesized that some genes in the WNT signaling network have a higher mutational burden in myelomeningocele subjects than in reference subjects in gnomAD. Exome sequencing data from 511 myelomeningocele subjects was obtained in-house and data from 29,940 ethnically matched subjects was provided by version 2 of the publicly available Genome Aggregation Database. To compare mutational burden, we collapsed rare deleterious variants across each of 523 human WNT signaling genes in case and reference populations. Ten WNT signaling genes were disrupted with a higher mutational burden among Mexican American myelomeningocele subjects compared to reference subjects (Fishers exact test, P ≤ 0.05) and seven different genes were disrupted among individuals of European ancestry compared to reference subjects. Gene ontology enrichment analyses indicate that genes disrupted only in the Mexican American population play a role in planar cell polarity whereas genes identified in both populations are important for the regulation of canonical WNT signaling. In summary, evidence for WNT signaling genes that may contribute to myelomeningocele in humans is presented and discussed.

Identification of novel candidate risk genes for myelomeningocele within the glucose homeostasis/oxidative stress and folate/one-carbon metabolism networks

Background

Neural tube defects (NTDs) are the second most common complex birth defect, yet, our understanding of the genetic contribution to their development remains incomplete. Two environmental factors associated with NTDs are Folate and One Carbon Metabolism (FOCM) and Glucose Homeostasis and Oxidative Stress (GHOS). Utilizing next‐generation sequencing of a large patient cohort, we identify novel candidate genes in these two networks to provide insights into NTD mechanisms.

Methods

Exome sequencing (ES) was performed in 511 patients, born with myelomeningocele, divided between European American and Mexican American ethnicities. Healthy control data from the Genome Aggregation database were ethnically matched and used as controls. Rare, high fidelity, nonsynonymous predicted damaging missense, nonsense, or canonical splice site variants in independently generated candidate gene lists for FOCM and GHOS were identified. We used a gene‐based collapsing approach to quantify mutational burden in case and controls, with the control cohort estimated using cumulative allele frequencies assuming Hardy–Weinberg equilibrium.

Results

We identified 45 of 837 genes in the FOCM network and 22 of 568 genes in the GHOS network as possible NTD risk genes with p < 0.05. No nominally significant risk genes were shared between ethnicities. Using a novel approach to mutational burden we identify 55 novel NTD risk associations.

Conclusions

We provide a means of utilizing large publicly available sequencing datasets as controls for sequencing projects examining rare disease. This approach confirmed existing risk genes for myelomeningocele and identified possible novel risk genes. Lastly, it suggests possible distinct genetic etiologies for this malformation between different ethnicities.

An ontology for developmental processes and toxicities of neural tube closure

In recent years, the development and implementation of animal-free approaches to chemical and pharmaceutical hazard and risk assessment has taken off. Alternative approaches are being developed starting from the perspective of human biology and physiology. Neural tube closure is a vital step that occurs early in human development. Correct closure of the neural tube depends on a complex interplay between proteins along a number of protein concentration gradients. The sensitivity of neural tube closure to chemical disturbance of signalling pathways such as the retinoid pathway, is well known. To map the pathways underlying neural tube closure, literature data on the molecular regulation of neural tube closure were collected. As the process of neural tube closure is highly conserved in vertebrates, the extensive literature available for the mouse was used whilst considering its relevance for humans. Thus, important cell compartments, regulatory pathways, and protein interactions essential for neural tube closure under physiological circumstances were identified and mapped. An understanding of aberrant processes leading to neural tube defects (NTDs) requires detailed maps of neural tube embryology, including the complex genetic signals and responses underlying critical cellular dynamical and biomechanical processes. The retinoid signaling pathway serves as a case study for this ontology because of well-defined crosstalk with the genetic control of neural tube patterning and morphogenesis. It is a known target for mechanistically-diverse chemical structures that disrupt neural tube closure The data presented in this manuscript will set the stage for constructing mathematical models and computer simulation of neural tube closure for human-relevant AOPs and predictive toxicology.

Maternal Inositol Status and Neural Tube Defects: A Role for the Human Yolk Sac in Embryonic Inositol Delivery?

Supplementation with myo-inositol during the periconceptional period of pregnancy may ameliorate the recurrence risk of having a fetus affected by a neural tube defect (NTD; e.g., spina bifida). This could be of particular importance in providing a means for preventing NTDs that are unresponsive to folic acid. This review highlights the characteristics of inositol and describes the role of myo-inositol in the prevention of NTDs in rodent studies and the evidence for its efficacy in reducing NTD risk in human pregnancy. The possible reduction in NTD risk by maternal myo-inositol implies functional and developmentally important maternal-embryonic inositol interrelationships and also suggests that embryonic uptake of myo-inositol is crucial for embryonic development. The establishment of active myo-inositol cellular uptake mechanisms in the embryonic stages of human pregnancy, when the neural tube is closing, is likely to be an important determinant of normal development. We draw attention to the generation of materno-fetal inositol concentration gradients and relationships, and outline a transport pathway by which myo-inositol may be delivered to the early developing human embryo. These considerations provide novel insights into the mechanisms that may underpin inositol's ability to confer embryonic developmental benefit.

miR-322 treatment rescues cell apoptosis and neural tube defect formation through silencing NADPH oxidase 4

AIMS

Failure of neural tube closure resulting from excessive apoptosis leads to neural tube defects (NTDs). NADPH oxidase 4 (NOX4) is a critical mediator of cell growth and death, yet its role in NTDs has never been characterized. NOX4 is a potential target of miR-322, and we have previously demonstrated that miR-322 was involved in high glucose-induced NTDs. In this study, we investigated the effect of NOX4 on the embryonic neuroepithelium in NTDs and reveal a new regulatory mechanism for miR-322 that disrupts neurulation by ameliorating cell apoptosis.

METHODS

All-trans-retinoic acid (ATRA)-induced mouse model was utilized to study NTDs. RNA pull-down and dual-luciferase reporter assays were used to confirm the interaction between NOX4 and miR-322. In mouse neural stem cells and whole-embryo culture, Western blot and TUNEL were carried out to investigate the effects of miR-322 and NOX4 on neuroepithelium apoptosis in NTD formation.

RESULTS

NOX4, as a novel target of miR-322, was upregulated in ATRA-induced mouse model of NTDs. In mouse neural stem cells, the expression of NOX4 was inhibited by miR-322; still further, NOX4-triggered apoptosis was also suppressed by miR-322. Moreover, in whole-embryo culture, injection of the miR-322 mimic into the amniotic cavity attenuated cell apoptosis in NTD formation by silencing NOX4.

CONCLUSION

miR-322/NOX4 plays a crucial role in apoptosis-induced NTD formation, which may provide a new understanding of the mechanism of embryonic NTDs and a basis for potential therapeutic target against NTDs.

Complement factors and alpha-fetoprotein as biomarkers for noninvasive prenatal diagnosis of neural tube defects

Neural tube defects (NTDs) are serious congenital malformations. In this study, we aimed to identify more specific and sensitive maternal serum biomarkers for noninvasive NTD screenings. We collected serum from 37 pregnant women carrying fetuses with NTDs and 38 pregnant women carrying normal fetuses. Isobaric tags for relative and absolute quantitation were conducted for differential proteomic analysis, and an enzyme-linked immunosorbent assay was used to validate the results. We then used a support vector machine (SVM) classifier to establish a disease prediction model for NTD diagnosis. We identified 113 differentially expressed proteins; of these, 23 were either up- or downregulated 1.5-fold or more, including five complement proteins (C1QA, C1S, C1R, C9, and C3); C3 and C9 were downregulated significantly in NTD groups. The accuracy rate of the SVM model of the complement factors (including C1QA, C1S, and C3) was 62.5%, with 60% sensitivity and 67% specificity, while the accuracy rate of the SVM model of alpha-fetoprotein (AFP, an established biomarker for NTDs) was 62.5%, with 75% sensitivity and 50% specificity. Combination of the complement factor and AFP data resulted in the SVM model accuracy of 75%, and receiver operating characteristic curve analysis showed 75% sensitivity and 75% specificity. These data suggest that a disease prediction model based on combined complement factor and AFP data could serve as a more accurate method of noninvasive prenatal NTD diagnosis.

Modeling shows high potential of folic acid-fortified salt to accelerate global prevention of major neural tube defects

BACKGROUND

We estimated the global proportion of folic acid-preventable spina bifida and anencephaly (FAP SBA) potentially prevented through mandatory double fortification of iodized salt with folic acid.

METHODS

Using United Nations Children's Fund (UNICEF) and Global Fortification Data Exchange (GFDx) data sets, we modeled country-specific number of FAP SBA cases prevented annually using (a) current coverage of the salt in households worldwide and (b) expected daily amount of folic acid intake from folic acid-fortified iodized salt. Our evidence-based modeling strategy assumed mandatory folic acid fortification of salt at 20 ppm, and that at 200 μg/day intake of folic acid through fortified salt, should achieve 100% prevention of all FAP SBA in countries.

RESULTS

One hundred countries that have data on percent of households consuming iodized salt globally were examined; 55 of them have ≥80% households consuming iodized salt. Our model estimated approximately 180,000 cases of FAP SBA could be prevented in these 100 countries through folic acid-fortified iodized salt, and 150,000 of them would be in countries where ≥80% households consuming iodized salt that can be potentially fortified with folic acid. Salt fortification with folic acid could contribute to the prevention of about 65% global FAP SBA cases annually.

CONCLUSIONS

Our evidence-based model shows that there is high potential to prevent FAP SBA using folic acid-fortified iodized salt. Prevention will reach countries where there is a limited reach of centrally processed folic acid-fortified wheat or maize flour. If this intervention is made feasible by the salt industry, it can accelerate the prevention of FAP SBA significantly.

Magnitude and Associated Factors of Neural Tube Defects in Ethiopia: A Systematic Review and Meta-Analysis

Neural tube defects remain a major problem in developing countries, but there are limited comprehensive national reports to date in Ethiopia. Therefore, this study aimed to assess the prevalence of neural tube defects and associated factors in Ethiopia. Electronic databases and other sources were used to retrieve studies. Fifteen out of 862 studies were included in the final analysis. The estimated pooled prevalence of neural tube defects among children in Ethiopia was 63.3 cases per 10 000 children. The pooled prevalence of spinal bifida, anencephaly, and encephalocele was 41.09, 18.90, and 1.07 per 10 000 children, respectively. Previous family history and unplanned pregnancy were risk factors for neural tube defects. Folic acid supplementation during the first trimester of pregnancy was found to be protective. Neural tube defects are widespread in Ethiopia. Hence, fortification of food with folic acid or folic acid supplementation during childbearing age is recommended.

Oxidative stress response associates with the teratogenic effects of benzyl butyl phthalate (BBP)

Benzyl butyl phthalate (BBP) is a persistent environmental pollutant. BBP exposure and the possible effects on human neural tube defects (NTDs) remain elusive. In this study, we found that the detection ratio of positive BBP and its metabolites in maternal urine was obviously higher in NTDs' population than that in normal controls by GC-MS (P < 0.01, P < 0.05, respectively). Animal experiments showed that BBP treatment induced developmental toxicity in chick embryo by enhancing the levels of oxidative stress and cell apoptosis (P < 0.01). More interestingly, the supplement of high-dose choline (CHO, 10 ⁵  μg/mL) could partially restore the teratogenic effects of BBP by inhibiting the occurrence of oxidative stress. Our data collectively suggest that BBP exposure may disturb neural tube development by strengthening oxidative stress. CHO can partially restore the toxicity effects of BBP. This study may provide new insight for NTD prevention.

Functional Validation of CLDN Variants Identified in a Neural Tube Defect Cohort Demonstrates Their Contribution to Neural Tube Defects

Neural tube defects (NTDs) are severe malformations of the central nervous system that affect 1–2 individuals per 2,000 births. Their etiology is complex and involves both genetic and environmental factors. Our recent discovery that simultaneous removal of Cldn3, -4, and -8 from tight junctions results in cranial and spinal NTDs in both chick and mouse embryos suggests that claudins play a conserved role in neural tube closure in vertebrates. To determine if claudins were associated with NTDs in humans, we used a Fluidigm next generation sequencing approach to identify genetic variants in CLDN loci in 152 patients with spinal NTDs. We identified eleven rare and four novel missense mutations in ten CLDN genes. In vivo validation of variant pathogenicity using a chick embryo model system revealed that overexpression of four variants caused a significant increase in NTDs: CLDN3 A128T, CLDN8 P216L, CLDN19 I22T, and E209G. Our data implicate rare missense variants in CLDN genes as risk factors for spinal NTDs and suggest a new family of proteins involved in the pathogenesis of these malformations.

Understanding the Mothers of Children with Spina Bifida and Hydrocephalus in Tanzania

OBJECTIVE

To identify if there are cultural, medical, educational, economic, nutritional and geographic barriers to the prevention and treatment of spina bifida and hydrocephalus.

METHODS

The mothers of infants with spina bifida and hydrocephalus admitted to Muhimbilli Orthopaedic Institute, Dar Es Salaam, Tanzania, between 2013 and 2014 were asked to complete a questionnaire. A total of 299 infants were identified: 65 with myelomeningoceles, 19 with encephaloceles, and 215 with isolated hydrocephalus. The questionnaire was completed by 294 of the mothers.

RESULTS

There was a high variation in the geographic origin of the mothers. Approximately 85% traveled from outside of Dar Es Salaam. The mean age was 29 (15-45) years old with a parity of 3 (1-10). The rates of consanguinity, obesity, antiepileptic medication, HIV seropositivity, and family history were 2%, 13%, 0%, 2%, and 2%, respectively. A maize-based diet was found in 84%, and only 3% of woman took folic acid supplementation, despite 61% of mothers stating that they wished to conceive another baby. Unemployment was high (77%), a low level of education was common (76% not attended any school or obtaining a primary level only), and 20% were single mothers. Hospital only was the preferred method of treatment for 94% of the mothers, and 85% of the babies were born in a hospital.

CONCLUSIONS

Our study highlights some of the cultural, educational, geographic, nutritional, and economic difficulties in the prevention and management of spina bifida and hydrocephalus in Tanzania.

Folic acid supplementation in Italian women during pregnancy: A cross-sectional study conducted in general practice

OBJECTIVES

The association between folate insufficiency and congenital neural tube defects has been extensively investigated since the 1990s. To reach an adequate intake of folic acid (FA), improving folate status through periconceptional supplementation with FA, promotion of the consumption of foods rich in natural folates, and appropriate use of fortified foods is recommended. The aim of the present study was to investigate the supplementation of FA in a sample of pregnant women referred to general practice services in Italy, with a focus on the quality of information received by fertile women.

METHODS

Participants were recruited from patients admitted to 44 general practice offices enrolled in the Italian Society of Preventive Medicine and Lifestyle study and located in Italy throughout the national territory. A questionnaire for the evaluation of FA supplementation was administered by the general practitioners (GPs). The interviewed subjects were asked to provide information about pregnancy characteristics, nutritional habits, lifestyle and risk factors, information sources, and knowledge about FA.

RESULTS

This study included 328 participants. The percentage of women who did not take any FA supplements was 16.8%, and 66.4% of women started FA supplementation only after finding out they were pregnant. Only 16.8% of women started FA supplementation 12 wk before the beginning of pregnancy. The lack of supplementation with FA, as well as the incorrect adherence to the existing FA supplementation protocol, is attributable to different social (e.g., immigration, place of residence, job employment) and cultural (e.g., educational level, knowledge about FA) factors, the relatively poor planning of pregnancies, and the lack of information concerning the need for FA supplementation in the prepregnancy period. Finally, GPs and gynecologists are the only sources of information on the importance of FA supplementation.

CONCLUSIONS

The adherence of women to FA supplementation before pregnancy is still insufficient. The GP role in preconception care, and the promotion of FA supplementation, needs to be emphasized and further promoted.

Neonatal ten-year retrospective study on neural tube defects in a second level University Hospital

BACKGROUND

Aim of this retrospective study was to describe clinical characteristics, diagnostic work-up, management and follow-up of newborns with neural tube defects (NTDs), admitted to the Mother and Child Department of the University Hospital of Palermo, in a ten years period.

METHODS

The medical records of 7 newborns (5 males and 2 females) admitted, over a 10-year period from January 2010 to March 2020, to our Department on the first day of life were reviewed. Analyzed data were related to familiar and/or maternal risk factors (consanguinity, maternal preexisting and/or gestational diseases, exposure to teratogen/infectious agents, lack of preconception folic acid supplement), demographic (ethnicity/origin, residence) and clinical features (eventual use of assisted reproduction techniques, prenatal diagnosis, gestational age, fetal presentation, type of delivery, birth weight, preoperative imaging, antibiotics and analgesics use, description of the surgery intervention, length of hospital stay, comorbidities, complications), and follow-up.

RESULTS

In our sample we observed a wide spectrum of NTDs: 3 newborns had open NTDs, namely myelomeningocele (2 lumbosacral, one of which associated with extradural lipoma, and 1 sacral), and 4 closed ones, including 2 with meningocele (occipital), 1 filar lipoma associated with dermal sinus, and 1 terminal myelocystocele. Our patients were discharged between 8 and 22 days of life. The neurodevelopmental follow-up showed a favorable outcome for 4 of the 7 patients, and the appearance over time of neurological impairment (motor and/or autonomic) in the newborns with open NTDs.

CONCLUSIONS

This study describes familiar and/or maternal risk factors and demographic and clinical features of a single-center series of newborns with NTDs. It may provide a further outline of the actual phenotypic spectrum of these malformations, and new insights into epidemiological aspects and comprehensive management of the patients, including diagnostic work-up and follow-up evaluations.

Closing in on Mechanisms of Open Neural Tube Defects

Neural tube defects (NTDs) represent a failure of the neural plate to complete the developmental transition to a neural tube. NTDs are the most common birth anomaly of the CNS. Following mandatory folic acid fortification of dietary grains, a dramatic reduction in the incidence of NTDs was observed in areas where the policy was implemented, yet the genetic drivers of NTDs in humans, and the mechanisms by which folic acid prevents disease, remain disputed. Here, we discuss current understanding of human NTD genetics, recent advances regarding potential mechanisms by which folic acid might modify risk through effects on the epigenome and transcriptome, and new approaches to study refined phenotypes for a greater appreciation of the developmental and genetic causes of NTDs.

Rare copy number variations of planar cell polarity genes are associated with human neural tube defects

Select single-nucleotide variants in planar cell polarity (PCP) genes are associated with increased risk for neural tube defects (NTDs). However, whether copy number variants (CNVs) in PCP genes contribute to NTDs is unknown. Considering that CNVs are implicated in several human developmental disorders, we hypothesized that CNVs in PCP genes may be causative factors to human NTDs. DNA from umbilical cord tissues of NTD-affected fetuses and parental venous blood samples were collected. We performed a quantitative analysis of copy numbers of all exon regions in the VANGL1, VANGL2, CELSR1, SCRIB, DVL2, DVL3, and PTK7 genes using a CNVplex assay. Quantitative real-time PCR (qPCR) was carried out to confirm the results of CNV analysis. As a result, 16 CNVs were identified among the NTDs. Of these CNVs, 5 loci were identified in 11 NTD probands with CNVs involving DVL2 (exons 1-15), VANGL1 (exons 1-7, exon 8), and VANGL2 (exons 5-8, exons 7 and 8). One CNV (DVL2 exons 1-15) was a duplication and the remaining 15 CNVs were deletions. Eleven CNVs were confirmed by qPCR. One de novo CNV in VANGL1 and one DVL2 were detected from two cases. Compared with unaffected control populations in 1000 Genome, ExAC, MARRVEL, DGV, and dbVar databases, the frequencies of de novo deletion in VANGL1 (1.14%) and de novo duplication in DVL2 (0.57%) were significantly higher in our NTD subjects (p < 0.05). This study demonstrates that de novo CNVs in PCP genes, notably deletions in VANGL1 and gains in DVL2, could contribute to the risk of NTDs.

Maternal low body mass index is a risk factor for fetal ductal constriction following indomethacin use among women undergoing fetal repair of spina bifida

OBJECTIVES

The objectives were to determine the prevalence of and to identify risk factors associated with constriction of the fetal ductus arteriosus (DA) following perioperative indomethacin use for fetal myelomeningocele (MMC) repair. Study design A retrospective chart review study included 100 consecutive fetuses who underwent fetal MMC repair between 2011 and 2018. All patients had fetal echocardiography (FE) on postoperative day (POD)#1 and 2 to detect constriction of the DA. All patients received indomethacin for tocolysis using a standardized protocol. Multivariate regression analysis was carried out to identify the predictors for fetal ductal constriction.

RESULTS

Eighty patients met our study eligibility criteria. Median gestational age at time of surgery was 25 (24-25) weeks. Constriction of the DA was detected in 14 fetuses (17.5%). In five fetuses, this was observed on POD# 1, in seven on POD# 2, and in two on both days. The only independent risk factor for predicting DA constriction was maternal body mass index (BMI) <25 kg/m² (P = .002).

CONCLUSION

Indomethacin therapy following fetal MMC surgery requires careful daily FE surveillance. The association of DA constriction and low BMI suggests that BMI-based dosing of indomethacin may be recommended for perioperative tocolysis in fetal MMC surgery.

Intra-Amniotic Delivery of CRMP4 siRNA Improves Mesenchymal Stem Cell Therapy in a Rat Spina Bifida Model

Neural tube defects (NTDs) result in prenatal mortality and lifelong morbidity, and available treatments have limited efficacy. We previously suggested that prenatal bone marrow-derived mesenchymal stem cell (BMSC) transplantation could treat neuron deficiency in NTD rats; however, BMSC-based therapy is limited by the low survival rate of BMSCs when used to treat severe NTDs. Herein, a new therapy using combined BMSC transplantation and small interfering RNA of collapsin response mediator protein 4 (CRMP4 siRNA), which was identified as a novel potential target for the NTD treatment, is proposed. The intra-amniotic CRMP4 siRNA, BMSC, and CRMP4 siRNA + BMSC injections repaired skin lesions, improved motor neural function, reduced neuronal apoptosis, and promoted expression of neural differentiation-related molecules and neurotrophic factors in the spinal cord of spina bifida rat fetuses. Therapeutic effects in the CRMP4 siRNA + BMSC injection group were superior to those of the CRMP4 siRNA only or BMSC only injection groups. CRMP4 siRNA + BMSC injection resulted in a 45.38% reduction in the skin lesion area and significantly shorter latency and higher amplitude of motor-evoked potentials (MEPs) in spina bifida fetuses. Our results suggest that intrauterine Ad-CRMP4 siRNA delivery with BMSCs is an innovative platform for developing fetal therapeutics to safely and efficaciously treat NTDs.

Maternal Folic Acid Supplementation Mediates Offspring Health via DNA Methylation

The clinical significance of periconceptional folic acid supplementation (FAS) in the prevention of neonatal neural tube defects (NTDs) has been recognized for decades. Epidemiological data and experimental findings have consistently been indicating an association between folate deficiency in the first trimester of pregnancy and poor fetal development as well as offspring health (i.e., NTDs, isolated orofacial clefts, neurodevelopmental disorders). Moreover, compelling evidence has suggested adverse effects of folate overload during perinatal period on offspring health (i.e., immune diseases, autism, lipid disorders). In addition to several single-nucleotide polymorphisms (SNPs) in genes related to folate one-carbon metabolism (FOCM), folate concentrations in maternal serum/plasma/red blood cells must be considered when counseling FAS. Epigenetic information encoded by 5-methylcytosines (5mC) plays a critical role in fetal development and offspring health. S-adenosylmethionine (SAM), a methyl donor for 5mC, could be derived from FOCM. As such, folic acid plays a double-edged sword role in offspring health via mediating DNA methylation. However, the underlying epigenetic mechanism is still largely unclear. In this review, we summarized the link across DNA methylation, maternal FAS, and offspring health to provide more evidence for clinical guidance in terms of precise FAS dosage and time point. Future studies are, therefore, required to set up the reference intervals of folate concentrations at different trimesters of pregnancy for different populations and to clarify the epigenetic mechanism for specific offspring diseases.

Neurosurgical training and global health education: systematic review of challenges and benefits of in-country programs in the care of neural tube defects

OBJECTIVE

The recognition that neurosurgeons harbor great potential to advocate for the care of individuals with neural tube defects (NTDs) globally has sounded as a clear call to action; however, neurosurgical care and training in low- and middle-income countries (LMICs) present unique challenges that must be considered. The objective of this study was to systematically review publications that describe the challenges and benefits of participating in neurosurgery-related training programs in LMICs in the service of individuals with NTDs.

METHODS

Using MEDLINE (PubMed), the authors conducted a systematic review of English- and Spanish-language articles published from 1974 to 2019 that describe the experiences of in-country neurosurgery-related training programs in LMICs. The inclusion criteria were as follows—1) population/exposure: US residents, US neurosurgeons, and local in-country medical staff participating in neurosurgical training programs aimed at improving healthcare for individuals with NTDs; 2) comparison: qualitative studies; and 3) outcome: description of the challenges and benefits of neurosurgical training programs. Articles meeting these criteria were assessed within a global health education conceptual framework.

RESULTS

Nine articles met the inclusion criteria, with the majority of the in-country neurosurgical training programs being seen in subregions of Africa (8/9 [89%]) and one in South/Central America. US-based residents and neurosurgeons who participated in global health neurosurgical training had increased exposure to rare diseases not common in the US, were given the opportunity to work with a collaborative team to educate local healthcare professionals, and had increased exposure to neurosurgical procedures involved in treating NTDs. US neurosurgeons agreed that participating in international training improved their own clinical practices but also recognized that identifying international partners, travel expenses, and interference with their current practice are major barriers to participating in global health education. In contrast, the local medical personnel learned surgical techniques from visiting neurosurgeons, had increased exposure to intraoperative decision-making, and were given guidance to improve postoperative care. The most significant challenges identified were difficulties in local long-term retention of trained fellows and staff, deficient infrastructure, and lower compensation offered for pediatric neurosurgery in comparison to adult care.

CONCLUSIONS

The challenges and benefits of international neurosurgical training programs need to be considered to effectively promote the development of neurosurgical care for individuals with NTDs in LMICs. In this global health paradigm, future work needs to investigate further the in-country professionals’ perspective, as well as the related outcomes.

Amniotic fluid concentrations of soluble endoglin and endothelial cell-specific molecule-1 in pregnancies complicated with neural tube defects

Objective To determine the concentrations of soluble endoglin (sCD105) and endothelial cell-specific molecule-1 (ESM-1) in the amniotic fluid (AF) of pregnant women, and to investigate the relationship between these concentrations and neural tube defects (NTDs). Methods AF concentrations of sCD105 and ESM-1 were measured in the study group, which included 60 pregnant women complicated with NTDs, and 64 pregnant women with unaffected healthy fetuses (control group). The AF concentrations of sCD105 and ESM-1 in both groups were measured using enzyme-linked immunosorbent assay and compared. Results There were no significant differences in terms of the mean AF concentrations of sCD105 and ESM-1 between the groups (P=0.141, P=0.084, respectively). There was a significant difference between the AF sCD105 concentrations in those with gestational age <24 weeks (n=101) and ≥24 weeks (n=23) (X̅<24=76.35±126.62 vs. X≥24=39.87±58.32, P=0.041). AF ESM-1 concentrations were found to be statistically significant in the gestational age <22 weeks (n=90) and ≥22 weeks (n=34) groups (X̅<22=135.91±19.26 vs. X̅≥22=148.56±46.85, P=0.035). A positive and low-level relation at a statistically significant level was determined between the gestational age and AF ESM-1 concentration in the study group (r=0.257; P=0.048). Conclusion AF concentrations of sCD105 and ESM-1 were not associated with the development of NTDs. Unlike studies that reported that ESM-1 concentrations decreased in maternal plasma with increased gestational age, we determined an increase that was proportionate to gestational age in AF.

Evaluation of Neural Tube Defects (NTDs) After Exposure to Raltegravir During Pregnancy

OBJECTIVE

To evaluate the risk of neural tube defects (NTDs) after exposure to raltegravir during pregnancy.

METHODS

Exposures to raltegravir during pregnancy reported cumulatively through May 31, 2018, to the company safety database were reviewed to identify cases of NTDs. This database includes all reports of pregnancy from Merck-sponsored clinical trials, spontaneous postmarketing reports, and non-interventional data sources, including the Antiretroviral Pregnancy Registry (APR). Reports were classified as prospective (before knowledge of pregnancy outcome) or retrospective (after knowledge of pregnancy outcome). We also reviewed data from 2 ongoing pregnancy cohorts.

RESULTS

A total of 2426 pregnancies with reported outcomes were identified among women exposed to raltegravir: 1238 from the Merck database and 1188 from United Kingdom/Ireland and French pregnancy cohorts. Among all 2426 reports, 1991 were prospective. No cases of NTDs were identified among the prospective pregnancy reports, of which 767 were first trimester, including 456 in the periconception period (at or within 28 days after conception). Among the 435 retrospective reports, 3 NTD cases per APR criteria were identified (anencephaly, and 2 meningomyelocele), of which only one (meningomyelocele) was among exposures in the periconception period. Given the inherent limitations and bias of retrospective reports, it is not appropriate to calculate an incidence rate.

CONCLUSIONS

Prospectively collected pregnancy outcome data do not suggest an association between raltegravir exposure in the periconception period and NTDs. The current data support the updated DHHS and EACS treatment guidelines for use of raltegravir as a preferred integrase inhibitor in all stages of pregnancy.

Risk factors, presentation and outcome of meningomyelocele repair

Objective:

To determine the risk factors, presentation and outcome of meningomyelocele repair

Methods:

We reviewed 150 cases operated for meningomyelocele (MMC) at Jinnah Postgraduate Medical Centre Karachi between May 2015 and May 2018. Data of infants operated for MMC repair was extracted including socioeconomic status, maternal folate intake during pregnancy, head circumference, location and width of the defect, accompanying bladder and limb anomalies and treatments administered. Patients were followed up for a mean period of six months.

Results:

A total of 150 children were evaluated, out of which there were 83(55.3%) males and 67(44.7%) females. All belonged to low socio economic group and prenatal maternal folate intake as risk factor was positive in 103(68.7%) cases. Mean head circumference was 37.4 cm (range, 30.7 to 50 cm). Based on their location, 83(55%) of the defects were lumbosacral, 38(25.4%) were lumbar, 16(10.7%) were thoraco lumbar, 10(6.7%) were thoracic and three (2%) were cervical. Mean size of the meningomyelocele sac was 4.3 cm×5.6 cm (range, 1cm×2 cm to 11cm×8.4cm) and 21(14%) of the babies had a skin defect requiring flap. According to accompanying anomalies, 98(65.3%) of the babies had hydrocephalus, 13(9%) had club foot, four (2.7%) had diastematomyelia and three (2%) had tethered cord. Eighty seven (58%) patients had neurological deficit pre operatively and eight (5.4%) patients with normal power deteriorated after surgery out of which five (3.3%) developed paraplegia and three (2%) developed paraparesis. CSF leak was the major complication encountered in 16(11%) followed by meningitis in seven (5%), while the overall mortality was four (2.6%).

Conclusion:

The practice of periconceptional folic acid supplementation is essential to reduce the prevalence of neural tube defects (NTDs) in the developing world. Improved maternal nutrition with access to quality antenatal care is vital to decrease the prevalence and health burden.

Occipital mass in antenatal sonography

Biophysical profile (BPP) with ultrasound performed for a 32-year-old G5P3013 admitted at 31 weeks gestation with preterm, premature rupture of membranes (PPROM) noted an extracalvarial mass concerning for an encephalocele. Fetal MRI demonstrated edema over the occiput with no definable lesion visualized. Preterm labor requiring Cesarean delivery resulted in a live male neonate at 33 weeks gestation. An occipital mass was observed on neonatal physical exam. Postnatal ultrasound and MRI were consistent with cephalohematoma. This was surprising given the lack of vaginal delivery. We hypothesize that the occiput was positioned against the maternal ischial tuberosity and developed chronic trauma secondary to normal fetal movement over time, resulting in a cephalohematoma. Postnatal imaging confirmed this diagnosis as the mass gradually decreased and ultimately resolved. Although other etiologies are possible, this case emphasizes the need to consider cephalohematoma in the differential of CNS masses during pregnancy without abdominal trauma and/or vaginal delivery.

Prenatal diagnosis and clinical significance of cephalocele-A single institution experience and literature review

OBJECTIVES

To determine the frequency of genetic and additional structural abnormalities as well as pregnancy outcomes in fetuses with prenatally diagnosed cephalocele.

METHODS

A retrospective analysis of data retrieved from ultrasound examinations and genetic testing in fetuses with cephalocele diagnosed between 2006 and 2018 in a tertiary referral hospital along with a systematic literature search in the PubMed database on fetuses with prenatally diagnosed cephalocele.

RESULTS

Twenty-one out of 36 fetuses were found to have additional structural anomalies (58.3%). In four fetuses, anomalies were consistent with limb-body wall complex, in five with Meckel-Gruber syndrome, and in one with amniotic band syndrome. Genetic abnormalities were present in 11.1% of fetuses (trisomy 6; microdeletion 22q11.21; microduplication 16p13.11; pathogenic variant in gene CC2D2A). Twenty-eight pregnancies were terminated (77.8%; 28/36); two were miscarried (5.6%; 2/36). All six children from pregnancies that continued were liveborn but only two survived the surgery and developed neurological sequence. Overall survival rate was 25% (2/8) with 0% intact survival.

CONCLUSIONS

Additional structural anomalies are common in fetuses with cephalocele. A significant number of fetuses have genetic abnormalities, and a detailed genetic testing should be performed in all cases. The prognosis is poor with high mortality rate and 0% intact survival.

Loss of RAD9B impairs early neural development and contributes to the risk for human spina bifida

DNA damage response (DDR) genes orchestrating the network of DNA repair, cell cycle control, are essential for the rapid proliferation of neural progenitor cells. To date, the potential association between specific DDR genes and the risk of human neural tube defects (NTDs) has not been investigated. Using whole-genome sequencing and targeted sequencing, we identified significant enrichment of rare deleterious RAD9B variants in spina bifida cases compared to controls (8/409 vs. 0/298; p = .0241). Among the eight identified variants, the two frameshift mutants and p.Gln146Glu affected RAD9B nuclear localization. The two frameshift mutants also decreased the protein level of RAD9B. p.Ser354Gly, as well as the two frameshifts, affected the cell proliferation rate. Finally, p.Ser354Gly, p.Ser10Gly, p.Ile112Met, p.Gln146Glu, and the two frameshift variants showed a decreased ability for activating JNK phosphorylation. RAD9B knockdowns in human embryonic stem cells profoundly affected early differentiation through impairing PAX6 and OCT4 expression. RAD9B deficiency impeded in vitro formation of neural organoids, a 3D cell culture model for human neural development. Furthermore, the RNA-seq data revealed that loss of RAD9B dysregulates cell adhesion genes during organoid formation. These results represent the first demonstration of a DDR gene as an NTD risk factor in humans.

Up-regulation of RNA Binding Proteins Contributes to Folate Deficiency-Induced Neural Crest Cells Dysfunction

Folate deficiency has long been associated with the abnormal development of the neural crest cells (NCCs) and neural tube defects (NTDs). RNA binding proteins (RBPs) also play important roles in the normal neural crest development and neural tube formation. Nevertheless, the causative mechanism by which folate status influences human NCCs development and the RBPs functions remains unknown. In this study, we differentiated H9 human embryonic stem cells into neural crest cells (H9-NCCs) and then constructed three folic acid (FA) deficiency (FAD) H9-NCCs models in vitro. Decreased viability, impaired migration and promoted apoptosis of H9-NCCs were observed in three FAD H9-NCCs models. In addition, we showed that three RBPs, namely, hnRNPC, LARP6 and RCAN2, were up-regulated both in the FAD H9-NCC models in vitro and in the FAD mouse model in vivo. Knocking down of these three RBPs increased the H9-NCC viability and RCAN2 knockdown further promoted H9-NCC migration under FAD conditions. In normal culture condition, overexpression of RCAN2 and HnRNPC did not affect viabilities and migration of H9-NCCs while overexpression of LARP6 reduced the H9-NCC viability. Our findings demonstrate important regulatory effects of RBPs underlying FAD-induced impaired function of NCCs.

Guidelines and scientifically-based spina bifida care: Guidance across the lifespan in a global health context

The COVID-19 pandemic has reminded us that, if of nothing else, we live in a globalized community. Enthusiasm for evidenced-based medical knowledge is also contagious. Just as the incidence of SARS-CoV-2, the associated coronavirus, has had a borderless impact on global public health, so too neural tube defects have widespread significance. Previously, the concept of "blue marble health" was introduced as a policy framework to illustrate trends in the geographic distribution of health disparities affecting at-risk populations that live, not only in low-income countries, but also in pockets of the populace in wealthier nations. Subsequently, the Spina Bifida Association's Collaborative Care Network, through a cooperative agreement with the Centers for Disease Control and Prevention, recently produced the "Guidelines for the Care of People with Spina Bifida." While language differences, immigration, cultural beliefs, acculturation, local resources and social determinants of health, must be taken into account when these guidelines are implemented across the globe, they could not come at a more suitable time. The current digital age, as well as open access to this special issue, will ensure their ongoing wide distribution.

PRDM15 loss of function links NOTCH and WNT/PCP signaling to patterning defects in holoprosencephaly

Holoprosencephaly (HPE) is a congenital forebrain defect often associated with embryonic lethality and lifelong disabilities. Currently, therapeutic and diagnostic options are limited by lack of knowledge of potential disease-causing mutations. We have identified a new mutation in the PRDM15 gene (C844Y) associated with a syndromic form of HPE in multiple families. We demonstrate that C844Y is a loss-of-function mutation impairing PRDM15 transcriptional activity. Genetic deletion of murine Prdm15 causes anterior/posterior (A/P) patterning defects and recapitulates the brain malformations observed in patients. Mechanistically, PRDM15 regulates the transcription of key effectors of the NOTCH and WNT/PCP pathways to preserve early midline structures in the developing embryo. Analysis of a large cohort of patients with HPE revealed potentially damaging mutations in several regulators of both pathways. Our findings uncover an unexpected link between NOTCH and WNT/PCP signaling and A/P patterning and set the stage for the identification of new HPE candidate genes.

Cannabis Consumption Patterns Explain the East-West Gradient in Canadian Neural Tube Defect Incidence: An Ecological Study

While a known link between prenatal cannabis exposure and anencephaly exists, the relationship of prenatal cannabis exposure with neural tube defects (NTDs) generally has not been defined. Published data from Canada Health and Statistics Canada were used to assess this relationship. Both cannabis use and NTDs were shown to follow an east-west and north-south gradient. Last year cannabis consumption was significantly associated (P < .0001; cannabis use-time interaction P < .0001). These results were confirmed when estimates of termination for anomaly were used. Canada Health population data allowed the calculation of an NTD odds ratio) of 1.27 (95% confidence interval = 1.19-1.37; P < 10-11) for high-risk provinces versus the remainder with an attributable fraction in exposed populations of 16.52% (95% confidence interval = 12.22-20.62). Data show a robust positive statistical association between cannabis consumption as both a qualitative and quantitative variable and NTDs on a background of declining NTD incidence. In the context of multiple mechanistic pathways these strong statistical findings implicate causal mechanisms.

The Effect of Religious Belief on the Attitudes of Pregnant's Toward the Fetal Health

The purpose of this study is to identify the effect of religious beliefs on the attitudes of pregnant women toward the health of the fetus. Pregnancy, one of the important periods of life, is a special period in terms of affecting both the mother's and the baby's health. Health beliefs and attitudes are the factors that have effects on mother-baby death rates (mortality)-which is one of the most important criteria showing health level of societies. However, the literature has limited number of studies on this issue. Volunteer participants who applied to the Gynecology and Obstetrics Polyclinic were administered a questionnaire in order to identify the frequency of performing worship practices. Women's beliefs about their roles in determining their fetus's health were measured using Fetal Health Locus of Control (FHLC) scale. FHCL scale is composed of 3 sub-scales which include Internality Locus of Control (FHLC-I), Chance Locus of Control (FHLC-C), and Powerful Others Locus of Control (FHLC-P). Non-normally distributed scale scores were analyzed with Mann-Whitney U test for two independent groups and Kruskal-Wallis test for three independent groups. The scores obtained from all the sub-scales of the FHLC scale according to the praying groups were statistically significant (p = 0.008, p < 0.001, p < 0.001, respectively). The sub-scale scores were not statistically significant according to the tendency of giving alms (p = 0.269, p = 0.695, p = 0.079, respectively). The FHLC-I and FHLC-P scores did not indicate differences according to the tendency of going to pilgrimage (p = 0.914, p = 0.578), but FHLC-C scores were significantly higher in those who tended to go to pilgrimage (p = 0.004). There was a significant relationship between the tendency of performing prayer and going to pilgrimage and attitudes toward performing double-triple tests and oral glucose tolerance test (p = 0.002, p = 0.035, respectively). Religious beliefs were influential on the attitudes of pregnant women toward the health of the fetal. Gynecologists should consider patients' religious belief sensitivity while recommending them screening tests or planning their medication.

Cellular mechanisms underlying Pax3-related neural tube defects and their prevention by folic acid

Neural tube defects (NTDs), including spina bifida and anencephaly, are among the most common birth defects worldwide, but their underlying genetic and cellular causes are not well understood. Some NTDs are preventable by supplemental folic acid. However, despite widespread use of folic acid supplements and implementation of food fortification in many countries, the protective mechanism is unclear. Pax3 mutant (splotch; Sp2H ) mice provide a model in which NTDs are preventable by folic acid and exacerbated by maternal folate deficiency. Here, we found that cell proliferation was diminished in the dorsal neuroepithelium of mutant embryos, corresponding to the region of abolished Pax3 function. This was accompanied by premature neuronal differentiation in the prospective midbrain. Contrary to previous reports, we did not find evidence that increased apoptosis could underlie failed neural tube closure in Pax3 mutant embryos, nor that inhibition of apoptosis could prevent NTDs. These findings suggest that Pax3 functions to maintain the neuroepithelium in a proliferative, undifferentiated state, allowing neurulation to proceed. NTDs in Pax3 mutants were not associated with abnormal abundance of specific folates and were not prevented by formate, a one-carbon donor to folate metabolism. Supplemental folic acid restored proliferation in the cranial neuroepithelium. This effect was mediated by enhanced progression of the cell cycle from S to G2 phase, specifically in the Pax3 mutant dorsal neuroepithelium. We propose that the cell-cycle-promoting effect of folic acid compensates for the loss of Pax3 and thereby prevents cranial NTDs.

Genetic variants in GRHL3 and risk for neural tube defects: A case-control and case-parent triad/control study

BACKGROUND

Neural tube defects (NTDs) are the most common severe birth defects with complex etiologies. Previous studies conducted on animals have suggested that the Grhl3 gene is essential for closure of the spinal neural tube, but little evidence from human studies on the variants of GRHL3 gene has been provided, especially the common genetic variants.

METHODS

To investigate the relationship between common genetic variants of GRHL3 and the risk for NTDs, we performed a case-control study and a case-parent triad/control study. Fast-target enrichment sequencing was performed to screen exon regions from 503 NTD cases, and three tag SNPs (single nucleotide polymorphisms, including rs12030057, rs2486668, and rs545809) were selected according to the sequencing results. Then, Sequenom MassARRAY genotyping was performed in 757 case parents and 519 controls to obtain genotype information of the target variant sites among all NTD triads and controls.

RESULTS

The genotype distributions of all SNPs were in accordance with Hardy-Weinberg Equilibrium (HWE) in the control population. In the case-control study, significant associations were found between C27G genetic variants on rs2486668 and risk for spina bifida and encephalocele, respectively, under different genetic models. Consistently, in the case-parent triad/control study, GG genotype on rs2486668 was associated with increased risk for spina bifida, with a RR of 2.15 (95% CI: 1.20-3.83). However, no parent-of-origin effect was found for any tag SNPs.

CONCLUSION

The GRHL3 C67G missense variant may increase the risk for spina bifida and encephalocele phenotypes.

Novel mouse model of encephalocele: post-neurulation origin and relationship to open neural tube defects

Encephalocele is a clinically important birth defect that can lead to severe disability in childhood and beyond. The embryonic and early fetal pathogenesis of encephalocele is poorly understood and, although usually classified as a 'neural tube defect', there is conflicting evidence on whether encephalocele results from defective neural tube closure or is a post-neurulation defect. It is also unclear whether encephalocele can result from the same causative factors as anencephaly and open spina bifida, or whether it is aetiologically distinct. This lack of information results largely from the scarce availability of animal models of encephalocele, particularly ones that resemble the commonest, nonsyndromic human defects. Here, we report a novel mouse model of occipito-parietal encephalocele, in which the small GTPase Rac1 is conditionally ablated in the (non-neural) surface ectoderm. Most mutant fetuses have open spina bifida, and some also exhibit exencephaly/anencephaly. However, a proportion of mutant fetuses exhibit brain herniation, affecting the occipito-parietal region and closely resembling encephalocele. The encephalocele phenotype does not result from defective neural tube closure, but rather from a later disruption of the surface ectoderm covering the already closed neural tube, allowing the brain to herniate. The neuroepithelium itself shows no downregulation of Rac1 and appears morphologically normal until late gestation. A large skull defect overlies the region of brain herniation. Our work provides a new genetic model of occipito-parietal encephalocele, particularly resembling nonsyndromic human cases. Although encephalocele has a different, later-arising pathogenesis than open neural tube defects, both can share the same genetic causation.

Analysis of Mortality among Neonates and Children with Spina Bifida: An International Registry-Based Study, 2001-2012

BACKGROUND

Medical advancements have resulted in better survival and life expectancy among those with spina bifida, but a significantly increased risk of perinatal and postnatal mortality for individuals with spina bifida remains.

OBJECTIVES

To examine stillbirth and infant and child mortality among those affected by spina bifida using data from multiple countries.

METHODS

We conducted an observational study, using data from 24 population- and hospital-based surveillance registries in 18 countries contributing as members of the International Clearinghouse for Birth Defects Surveillance and Research (ICBDSR). Cases of spina bifida that resulted in livebirths or stillbirths from 20 weeks' gestation or elective termination of pregnancy for fetal anomaly (ETOPFA) were included. Among liveborn spina bifida cases, we calculated mortality at different ages as number of deaths among liveborn cases divided by total number of liveborn cases with spina bifida. As a secondary outcome measure, we estimated the prevalence of spina bifida per 10 000 total births. The 95% confidence interval for the prevalence estimate was estimated using the Poisson approximation of binomial distribution.

RESULTS

Between years 2001 and 2012, the overall first-week mortality proportion was 6.9% (95% CI 6.3, 7.7) and was lower in programmes operating in countries with policies that allowed ETOPFA compared with their counterparts (5.9% vs. 8.4%). The majority of first-week mortality occurred on the first day of life. In programmes where information on long-term mortality was available through linkage to administrative databases, survival at 5 years of age was 90%-96% in Europe, and 86%-96% in North America.

CONCLUSIONS

Our multi-country study showed a high proportion of stillbirth and infant and child deaths among those with spina bifida. Effective folic acid interventions could prevent many cases of spina bifida, thereby preventing associated childhood morbidity and mortality.

Reducing inequities in preventable neural tube defects: the critical and underutilized role of neurosurgical advocacy for folate fortification

Neural tube defects (NTDs) are one of the greatest causes of childhood mortality and disability-adjusted life years worldwide. Global prevalence at birth is approximately 18.6 per 10,000 live births, with more than 300,000 infants with NTDs born every year. Substantial strides have been made in understanding the genetics, pathophysiology, and surgical treatment of NTDs, yet the natural history remains one of high morbidity and profound impairment of quality of life. Direct and indirect costs of care are enormous, which ensures profound inequities and disparities in the burden of disease in countries of low and moderate resources. All indices of disease burden are higher for NTDs in developing countries. The great tragedy is that the majority of NTDs can be prevented with folate fortification of commercially produced food. Unequivocal evidence of the effectiveness of folate to reduce the incidence of NTDs has existed for more than 25 years. Yet, the most comprehensive surveys of effectiveness of implementation strategies show that more than 100 countries fail to fortify, and consequently only 13% of folate-preventable spina bifida is actually prevented. Neurosurgeons harbor a disproportionate, central, and fundamental role in the management of NTDs and enjoy high standing in society. No organized group in medicine can speak as authoritatively or convincingly. As a result, neurosurgeons and organized neurosurgery harbor disproportionate potential to advocate for more comprehensive folate fortification, and thereby prevent the most common and severe birth defect to impact the human nervous system. Assertive, proactive, informed advocacy for folate fortification should be a central and integral part of the neurosurgical approach to NTDs. Only by making the prevention of dysraphism a priority can we best address the inequities often observed worldwide.

Low Prevalence of Folic Acid Supplementation during Pregnancy: A Multicenter Study in Vietnam

Periconceptional folic acid (FA) supplementation is recommended to prevent neural tube defects (NTDs), but little information is known about its use in Vietnam. It is important that FA supplements start to be taken when planning a pregnancy and continued through the first trimester to prevent NTDs, as the neural tube closes in the first month of pregnancy. However, FA supplementation in Vietnam is usually recommended to commence from the first antenatal visit, which is usually at 16 weeks, and very few women take FA before their first visit. This multicenter study aimed to determine the prevalence of FA supplement use and associated maternal characteristics in Vietnam. FA supplementation was assessed in 2030 singleton pregnant women between 2015 and 2016. In total, 654 (32.2%) women reported taking either supplements containing FA alone or multivitamins containing FA, and 505 (24.9%) reported correctly taking supplements containing FA alone. Women who were aged 30 years or over, had low education levels, had formal employment, and whose current pregnancy was first or unplanned were less likely to supplement with FA. Education programs are needed to encourage FA supplementation when contemplating pregnancy.

Perinatal mortality associated with congenital defects of the central nervous system in Colombia, 2005-2014

In Colombia, congenital anomalies are the second leading cause of death in children aged less than 1 year, and central nervous system (CNS) anomalies are the second most common cause within this group. The aim of the study is to determine the frequency of perinatal mortality attributable to CNS anomalies in Colombia between 2005 and 2014. Using data from the Integral Information System of Social Protection (SISPRO), we determined the perinatal mortality rate associated with CNS anomalies; we also determined frequency of mortality according to age, type of abnormality, year of presentation, and georeferencing. A total of 4706 deaths were recorded to be primarily caused by CNS anomalies (anencephaly and hydrocephalus) in departments and prominent urban centers. The perinatal mortality rate associated with CNS defects has remained relatively constant over the past several years. Major referral centers in the country registered the highest mortality rates. The impact of CNS defects increased with the decrease in infant mortality rates and other health issues. Reinforcement of primary and secondary prevention strategies is warranted for reducing its incidence.

Folate of pregnant women after a nationwide folic acid supplementation in China

Folate insufficiency during the periconceptional period increases the risk of neural tube defects (NTDs) in offspring, and folic acid supplementation substantially reduces the risk. Widespread large-scale folic acid supplementation (0.4-mg folic acid tablet) has been adopted as a main strategy to prevent NTDs in China since 2009. We examined folate concentrations in plasma and red blood cells (RBCs) of pregnant women and the factors associated with blood folate concentrations in a population with a high prevalence of NTDs in northern China. A cross-sectional survey was conducted in 2014, and 1,107 pregnant women were recruited from 11 county or city maternal and child health centres across Shanxi province. Microbiological assays were used to determine folate concentrations. Factors associated with blood folate insufficiency were identified. The median (25th and 75th percentiles) folate concentrations were 28.4 (17.6, 45.2) nmol L-1 and 1,001.2 (658.7, 1,402.5) nmol L-1 in plasma and RBCs, respectively. According to the proposed RBC (906 nmol L-1 ) concentrations for optimal NTD prevention, 42.4% participants had RBC folate insufficiency. Rural women had a higher proportion of folate insufficiency than urban women. Folic acid supplementation was the only factor associated with RBC folate insufficiency. A large proportion of women had RBC folate concentrations that are not optimal for the prevention of NTDs despite free access to folic acid supplements. Actions that aim to improve folic acid supplementation compliance are needed to reach the full potential of the nationwide folic acid supplementation programme in terms of NTD prevention.

Preconception Folic Acid Supplement Use in Immigrant Women (1999-2016)

This study examines how preconception folic acid supplement use varied in immigrant women compared with non-immigrant women. We analyzed national population-based data from Norway from 1999–2016, including 1,055,886 pregnancies, of which 202,234 and 7,965 were to 1st and 2nd generation immigrant women, respectively. Folic acid supplement use was examined in relation to generational immigrant category, maternal country of birth, and length of residence. Folic acid supplement use was lower overall in 1st and 2nd generation immigrant women (21% and 26%, respectively) compared with Norwegian-born women (29%). The lowest use among 1st generation immigrant women was seen in those from Eritrea, Ethiopia, Morocco, and Somalia (around 10%). The highest use was seen in immigrant women from the United States, the Netherlands, Denmark, and Iceland (>30%). Folic acid supplement use increased with increasing length of residence in immigrant women from most countries, but the overall prevalence was lower compared with Norwegian-born women even after 20 years of residence (adjusted odds ratio: 0.63; 95% confidence interval: 0.60–0.67). This study suggests that immigrant women from a number of countries are less likely to use preconception folic acid supplements than non-immigrant women, even many years after settlement.

Reductions in child mortality by preventing spina bifida and anencephaly: Implications in achieving Target 3.2 of the Sustainable Development Goals in developing countries

BACKGROUND

There is an opportunity to reduce child mortality by preventing folic acid-preventable spina bifida and anencephaly (FAP SBA) in developing countries. We estimated reductions in FAP SBA-associated child mortality in 69 countries with an immediate potential for mandatory fortification of wheat flour.

METHODS

Using data from multiple sources, we estimated the percent reductions in neonatal, infant, and under-five mortality that would have occurred by preventing FAP SBA; and the contributions of these reductions toward each country's Sustainable Development Goals (SDG) for child mortality reduction. We used the combined prevalence of spina bifida and anencephaly in selected countries before fortification, and estimated preventable child mortality associated with FAP SBA, assuming 0.5 per 1,000 live births as minimum achievable prevalence from mandatory fortification.

RESULTS

Annually, 56,785 live births with FAP SBA occurred in the 69 countries examined. Of these, about 49,680 (87%) would have resulted in deaths under age 5 years, and are preventable through mandatory folic acid fortification. On average, compared to current rates, prevention of FAP SBA would have reduced the neonatal, infant, and under-five mortality by 19% (95% uncertainty interval [UI]: 16-24%), 15% (UI: 13-17%), and 14%, (95% UI: 13-17%), respectively. Prevention of FAP SBA seemed to contribute toward achieving SDG on neonatal and under-five mortality in developing countries.

CONCLUSIONS

Prevention of FAP SBA will lead to notable and immediate reductions in child mortality. Many countries have an opportunity to effectively move toward child mortality-related SDG targets with existing milling infrastructure for food fortification.

Fetal myelomeningocele repair

Myelomeningocele is a congenital malformation that causes a spectrum of morbidity. With the standard of care now being in utero repair, the spectrum of morbidity has changed. The purpose of this article is to review the diagnosis, workup and treatment options of fetal myelomeningocele. We also review the obstetrical, neurological, gastrointestinal, urinary, and orthopedic outcomes of the in utero myelomeningocele repair.