When folic acid fails: Insights from 20 years of neural tube defect surveillance in South Carolina

The loop-tail mouse model displays open and closed caudal neural tube defects

Neural tube defects (NTDs) are the second most common cause of congenital malformations and are often studied in animal models. Loop-tail (Lp) mice carry a mutation in the Vangl2 gene, a member of the Wnt-planar cell polarity pathway. In Vangl2+/Lp embryos, the mutation induces a failure in the completion of caudal neural tube closure, but only a small percentage of embryos develop open spina bifida. Here, we show that the majority of Vangl2+/Lp embryos developed caudal closed NTDs and presented cellular aggregates that may facilitate the sealing of these defects. The cellular aggregates expressed neural crest cell markers and, using these as a readout, we describe a systematic method to assess the severity of the neural tube dorsal fusion failure. We observed that this defect worsened in combination with other NTD mutants, Daam1 and Grhl3. Besides, we found that in Vangl2+/Lp embryos, these NTDs were resistant to maternal folic acid and inositol supplementation. Loop-tail mice provide a useful model for research on the molecular interactions involved in the development of open and closed NTDs and for the design of prevention strategies for these diseases.

A case study of ReachAnother Foundation as a change champion for developing spina bifida neurosurgical care and advocating for primary prevention in Ethiopia

Spina bifida is a serious birth defect affecting the central nervous system, characterized by incomplete closure of the neural tube. Ethiopia has a very high prevalence of spina bifida, affecting about 40 cases per 10,000 births. Babies born with spina bifida require early closure surgery, done within the first 2-3 days after birth. Some babies need repeat surgeries to address complications, including hydrocephalus. Without medical care, babies have a high risk of death within the first 5 years of their life. Neurosurgical capacity for spina bifida closure surgery at birth is a relatively new development in Ethiopia. ReachAnother Foundation, a not-for-profit organization based in OR, USA, started work in Ethiopia in 2009 and has been instrumental in training neurosurgeons and improving treatment for spina bifida and hydrocephalus. Along with the development of neurosurgical care, the Foundation has invested in training multi-disciplinary teams to conduct patient aftercare and has launched a platform for improved patient outcomes research. As of year 2022, they support six spina bifida "Centers of Excellence" nationwide and are continuously advocating for primary prevention of spina bifida through mandatory fortification of staple foods in Ethiopia. This paper describes ReachAnother's efforts in Ethiopia in a short interval of time, benefiting numerous patients and families with spina bifida and anencephaly. We document this as a case study for other countries to model where resources are limited and the prevalence of spina bifida and hydrocephalus is high, especially in Asia and Africa.

Folic acid prescription practice for high-risk prevention of spina bifida at a tertiary care hospital in Addis Ababa, Ethiopia

PURPOSE

Mothers who have had a pregnancy affected by spina bifida are advised to take 4-5 mg/day folic acid pills to prevent recurrence. The folic acid prescription pattern was examined for high-risk mothers whose children received spina bifida surgery in an urban Ethiopian hospital.

METHODS

Data were analyzed from a large Ethiopian urban tertiary care hospital that provided spina bifida care. General practitioners recorded 5 mg/day folic acid prescriptions administered to mothers of infants with spina bifida born between January 2019 and June 2022.

RESULTS

Among 500 baby-mother pairs, 340 (68%) received a 120-day prescription for 5 mg/day folic acid pills. Of these 340 mothers, 331 (97%) received their folic acid prescription at their child's first or second patient encounter. Almost all mothers (94%) had documentation of only one prescription for the study duration. The percentage of mothers receiving at least one prescription varied by the baby's year of birth (2019:75%; 2020:92%; 2021:46%; Jan 2022 -June 2022:79%).

CONCLUSION

This prioritization of spina bifida recurrence prevention demonstrates feasibility for other healthcare centers in low-income countries. Sustained funds to provide women with free folic acid pills can favor high compliance and uptake of this prevention intervention.

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.

Systematic Classification of Spina Bifida

Spina bifida (SB) is an umbrella term for multiple conditions characterized by misclosure of vertebral arches. Neuropathologic findings in SB cases are often reported with imprecise and overlapping terminology. In view of the increasing identification of SB-associated genes and pathomechanisms, the precise description of SB subtypes is highly important. In particular, the term "myelomeningocele" is applied to various and divergent SB subtypes. We reevaluated 90 cases with SB (58 prenatal; 32 postnatal). The most frequent SB phenotype in our cohort was myeloschisis, which is characterized by an open neural plate with exposed ependyma (n = 28; 31.1%). An open neural plate was initially described in only in two-thirds of the myeloschisis cases. An additional 21 cases (23.3%) had myelomeningocele; 2 cases (2.2%) had a meningocele; and 21 cases (23.3%) had an unspecified SB aperta (SBA) subtype. Overall, the SB phenotype was corrected in about one-third of the cases. Our findings highlight that "myelomeningocele" and "SB aperta" cannot be used as synonymous terms and that myeloschisis is an underreported SB phenotype. Based on our findings and a review of literature we propose a classification of SB subtypes in SB occulta and the 3 SBA subtypes, meningocele, myelomeningocele, and myeloschisis.

Association of maternal risk factors with the recent rise of neural tube defects in Canada

BACKGROUND

We sought to assess the recent trend in NTD prevalence at birth in the post-folic acid food fortification era and to identify the maternal risk factors associated with that trend.

METHODS

We carried out a population-based study of all livebirths and stillbirths (including late pregnancy terminations) delivered in hospitals in Canada (excluding Quebec) from 2004 to 2015 (n = 3 439 330). We examined NTD birth prevalence by year, multiple pregnancy, maternal age, parity, pregestational diabetes, chronic illness, and problematic substance use. Poisson regression was used to quantify the association between spina bifida and cranial defects and maternal characteristics and other risk factors.

RESULTS

We identified 1517 non-chromosomal NTDs, yielding a birth prevalence of 4.4 per 10 000 total births. NTD prevalence rose from 3.6 in 2004 to 4.6 per 10 000 in 2015 (P_trend  = 0.03). Among NTD subtypes, only spina bifida showed a temporal increase (P_trend  = 0.03). Birth prevalence of spina bifida was higher among younger mothers, those with type 2 diabetes (rate ratio (RR) 3.74, 95% confidence interval (CI) 2.21, 6.35), chronic illness (RR 3.16, 95% CI 1.97, 5.07), and problematic substance use (RR 1.88, 95% CI 1.31, 2.71). Adjusting for risk factors attenuated the significant temporal trend in spina bifida (unadjusted average annual prevalence ratio (aAAPR) 1.016, 95% CI 1.001, 1.032; adjusted AAPR 1.014, 95% CI 0.998, 1.029).

CONCLUSIONS

Increases in the frequency of maternal risk factors such as pregestational diabetes mellitus, substance use, and chronic illness may be partly responsible for the recent rise in NTDs, particularly spina bifida.

Neural Tube Defects in Embryonic Life: Lessons Learned From 340 Early Pregnancy Failures

OBJECTIVES

The aim of this study was to evaluate the feasibility of sonographic assessment of the embryonic/fetal neural tube in nonviable pregnancies and to determine the defect incidence.

METHODS

Prospective analysis of transvaginally acquired 3-dimensional (3D) multiplanar and 3D surface-rendered volume sets of 340 cases of missed abortion between March 2010 and September 2015 was performed. Data regarding karyotype and postmortem examination as well as demographic features and the outcomes of subsequent pregnancies were evaluated.

RESULTS

In 223 cases, an embryo/fetus was detected and considered suitable for further evaluation: in 37 of 223 (16.6%) embryos/fetuses, a neural tube defect was present: 27 of 37 cephaloceles, 5 of 37 anencephalies/exencepahlies, 3 of 37 spina bifidas, 1 of 37 caudal regression syndrome, and 1 of 37 iniencephaly. Additional alterations were not observed. In 7 of 37 cases karyotyping was carried out and showed no aneuploidy. Eight subsequent pregnancies had a favorable outcome, with 1 ending in an intrauterine fetal death during the 22nd week of gestation. Maternal folic acid supplementation was provided for all subsequent pregnancies. No neural tube defects occurred.

CONCLUSIONS

Sonographic 3D evaluation of complete neural tube closure in embryonic/fetal demise is technically feasible and can be achieved in embryos with a crown-rump length greater than 8 mm. In 26 of 37 cases a defective closure site could be allocated to high-risk areas known for early embryonic demise. Regardless of the etiology of different neural tube defects, high-dose folic acid prophylaxis must be recommended in all cases. Sonographic evaluation of the neural tube, including 3D surface-rendered images, should be offered to every woman with a missed abortion because of the impact on subsequent pregnancies.

Key apoptotic genes APAF1 and CASP9 implicated in recurrent folate-resistant neural tube defects

Neural tube defects (NTDs) remain one of the most serious birth defects, and although genes in several pathways have been implicated as risk factors for neural tube defects via knockout mouse models, very few molecular causes in humans have been identified. Whole exome sequencing identified deleterious variants in key apoptotic genes in two families with recurrent neural tube defects. Functional studies in fibroblasts indicate that these variants are loss-of-function, as apoptosis is significantly reduced. This is the first report of variants in apoptotic genes contributing to neural tube defect risk in humans.

The recurrence risk of neural tube defects (NTDs) in a population with high prevalence of NTDs in northern China

Background

Although a number of studies have reported the recurrence risk of NTDs in developed countries, there is little data on the rate of recurrence of NTDs in northern China, a region of high prevalence of NTDs.

Methods

Based on the population-based birth defects surveillance system of five counties, we identified women who had an NTD affected pregnancy from 2004-2015 and a retrospective survey was conducted. The rate of recurrence of NTDs was calculated by the number of recurrent NTDs divided by the first NTDs. Maternal age, body mass index (BMI), gestational weeks, education, and occupation were collected. Information on folic acid (FA) supplements, time and dosage were also recorded.

Results

Among 851 women who had a previous NTD-affected pregnancy, there were 578 subsequent pregnancies, with 10 recurrent NTDs, a 1.7% recurrence rate. The recurrence rate was 1.5% and 2.6% for those taking FA supplements and without FA supplementation respectively. Women with recurrent NTDs had higher BMI before pregnancy compared to those who had a second pregnancy without NTDs. Among the recurrent NTDs, the majority were spina bifida.

Conclusions

The recurrence rate of NTDs was approximately five times higher than the overall prevalence in the same region of northern China. Risk of recurrence appeared lower among women who took FA supplements. These findings are consistent with the reduction in NTD frequency in the population since introduction of the nationwide FA supplement program. Data on recurrence rates in northern China will inform power calculations for future intervention studies.

Inositol, neural tube closure and the prevention of neural tube defects

Susceptibility to neural tube defects (NTDs), such as anencephaly and spina bifida is influenced by genetic and environmental factors including maternal nutrition. Maternal periconceptional supplementation with folic acid significantly reduces the risk of an NTD-affected pregnancy, but does not prevent all NTDs, and "folic acid non-responsive" NTDs continue to occur. Similarly, among mouse models of NTDs, some are responsive to folic acid but others are not. Among nutritional factors, inositol deficiency causes cranial NTDs in mice while supplemental inositol prevents spinal and cranial NTDs in the curly tail (Grhl3 hypomorph) mouse, rodent models of hyperglycemia or induced diabetes, and in a folate-deficiency induced NTD model. NTDs also occur in mice lacking expression of certain inositol kinases. Inositol-containing phospholipids (phosphoinositides) and soluble inositol phosphates mediate a range of functions, including intracellular signaling, interaction with cytoskeletal proteins, and regulation of membrane identity in trafficking and cell division. Myo-inositol has been trialed in humans for a range of conditions and appears safe for use in human pregnancy. In pilot studies in Italy and the United Kingdom, women took inositol together with folic acid preconceptionally, after one or more previous NTD-affected pregnancies. In nonrandomized cohorts and a randomized double-blind study in the United Kingdom, no recurrent NTDs were observed among 52 pregnancies reported to date. Larger-scale fully powered trials are needed to determine whether supplementation with inositol and folic acid would more effectively prevent NTDs than folic acid alone. Birth Defects Research 109:68-80, 2017. © 2016 The Authors Birth Defects Research Published by Wiley Periodicals, Inc.

Using state and provincial surveillance programs to reduce risk of recurrence of neural tube defects in the United States and Canada: A missed opportunity?

BACKGROUND

Once a woman has had a fetus or infant affected with a neural tube defect (NTD), the risk of recurrence is approximately 3%. This risk can be significantly reduced by folic acid supplement consumption during the periconceptional period; however, this requires women at risk to be adequately informed about the appropriate dosage and timing of supplement intake before planning another pregnancy. As birth defects surveillance programs are tasked with identifying and documenting NTD-affected pregnancies and births, they are in a unique position to support recurrence prevention activities.

METHODS

In 2015, we surveyed state and provincial birth defects surveillance programs to assess their NTD recurrence prevention activities. The online survey was sent to programs in 52 United States (U.S.) jurisdictions and all 13 provinces and territories in Canada. Findings were compared with a similar survey conducted in 2005 among U.S. programs.

RESULTS

In 2015, of the 44 U.S. and Canadian surveillance programs that responded, only 9 programs (7 U.S. and 2 Canadian) reported currently having activities specifically directed toward preventing NTD recurrence. Compared with a 2005 survey of U.S. programs, the number of U.S. programs working on NTD recurrence prevention decreased by almost 50% (from 13 to 7 programs).

CONCLUSION

The number of birth defects surveillance programs with NTD recurrence prevention activities has decreased over the past decade due to a range of barriers, most notably a lack of resources. However, while some recurrence prevention activities require part-time staff, other activities could be accomplished using minimal resources. Birth Defects Research (Part A) 106:875-880, 2016.© 2016 Wiley Periodicals, Inc.

Inositol for the prevention of neural tube defects: a pilot randomised controlled trial

Although peri-conceptional folic acid (FA) supplementation can prevent a proportion of neural tube defects (NTD), there is increasing evidence that many NTD are FA non-responsive. The vitamin-like molecule inositol may offer a novel approach to preventing FA-non-responsive NTD. Inositol prevented NTD in a genetic mouse model, and was well tolerated by women in a small study of NTD recurrence. In the present study, we report the Prevention of Neural Tube Defects by Inositol (PONTI) pilot study designed to gain further experience of inositol usage in human pregnancy as a preliminary trial to a future large-scale controlled trial to evaluate efficacy of inositol in NTD prevention. Study subjects were UK women with a previous NTD pregnancy who planned to become pregnant again. Of 117 women who made contact, ninety-nine proved eligible and forty-seven agreed to be randomised (double-blind) to peri-conceptional supplementation with inositol plus FA or placebo plus FA. In total, thirty-three randomised pregnancies produced one NTD recurrence in the placebo plus FA group (n 19) and no recurrences in the inositol plus FA group (n 14). Of fifty-two women who declined randomisation, the peri-conceptional supplementation regimen and outcomes of twenty-two further pregnancies were documented. Two NTD recurred, both in women who took only FA in their next pregnancy. No adverse pregnancy events were associated with inositol supplementation. The findings of the PONTI pilot study encourage a large-scale controlled trial of inositol for NTD prevention, but indicate the need for a careful study design in view of the unwillingness of many high-risk women to be randomised.