Are encephaloceles neural tube defects?

Effect of sugammadex administration on neural tube development in 48-h chick embryos

Sugammadex is a new generation drug that has led to significant changes in the practice of anesthesia. However, its effects on fetal development are not yet fully known. The aim of this study is to investigate the teratogenic effects of sugammadex on neural tube and embryonic development in early chick embryos. In this study, 50 0-day fertile specific non-pathogenic (SPF) eggs were used. Fifty eggs were divided into 5 different groups, each consisting of 10 pieces. While no substance was given to the control group at the 28th hour of the study, 4 different doses of sugammadex were administered to the experimental groups, respectively 2, 4, 8, 16 mg/kg. Cranio-caudal lengths of embryos, somite numbers, average number of argyrophilic nucleolar regulatory regions (AgNOR) per nucleus, total AgNOR area/total nuclear area (TAA/NA) ratios, Caspase-3 H-Score results, and presence of neural tube defect were compared among the groups. While the mean cranio-caudal lengths, somite counts, TAA/NA ratios and AgNOR counts of the embryos were found to be statistically significantly lower than the control group, Caspase-3 H-Score mean results were found to be significantly higher (p < .05). In addition, it was observed that there was an increase in neural tube patency and developmental delay. As a result, sugammadex crossing the placenta was revealed to increase the release of proapopitotic molecules and disrupt the developmental stages of embryos. Thus, it was determined that sugammadex in increased developmental delay and incidence of neural tube defects in early chick embryos with increased dose dependent. Despite these results, the effects of sugammadex on fetal development in in vivo and in vitro environments should be studied with further studies. RESEARCH HIGHLIGHTS: Sugammadex is a new generation drug that has led to significant changes in the practice of anesthesia. However, its effects on fetal development are not yet fully known. It has been observed that different doses of sugammadex increase the risk of neural tube defect development on chick embryos and slow the embryo development in a dose-dependent manner.

A non-coding insertional mutation of Grhl2 causes gene over-expression and multiple structural anomalies including cleft palate, spina bifida and encephalocele

Orofacial clefts, including cleft lip and palate (CL/P) and neural tube defects (NTDs) are among the most common congenital anomalies, but knowledge of the genetic basis of these conditions remains incomplete. The extent to which genetic risk factors are shared between CL/P, NTDs and related anomalies is also unclear. While identification of causative genes has largely focused on coding and loss of function mutations, it is hypothesized that regulatory mutations account for a portion of the unidentified heritability. We found that excess expression of Grainyhead-like 2 (Grhl2) causes not only spinal NTDs in Axial defects (Axd) mice but also multiple additional defects affecting the cranial region. These include orofacial clefts comprising midline cleft lip and palate and abnormalities of the craniofacial bones and frontal and/or basal encephalocele, in which brain tissue herniates through the cranium or into the nasal cavity. To investigate the causative mutation in the Grhl2Axd strain, whole genome sequencing identified an approximately 4 kb LTR retrotransposon insertion that disrupts the non-coding regulatory region, lying approximately 300 base pairs upstream of the 5' UTR. This insertion also lies within a predicted long non-coding RNA, oriented on the reverse strand, which like Grhl2 is over-expressed in Axd (Grhl2Axd) homozygous mutant embryos. Initial analysis of the GRHL2 upstream region in individuals with NTDs or cleft palate revealed rare or novel variants in a small number of cases. We hypothesize that mutations affecting the regulation of GRHL2 may contribute to craniofacial anomalies and NTDs in humans.

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

OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSION

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

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

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

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

Background

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

Methods

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

Results

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

Conclusion

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

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

Birth prevalence of encephalocele in Africa: a systematic review and meta-analysis

Objective

To identify the birth prevalence of encephalocele in Africa, 2020.

Methods

We carried out a systematic search of the following databases (PubMed/Medline, PubMed Central, Joanna Briggs Institute (JBI) Library, Cochrane Library, Web of Science, Google Scholar, Science Direct, African Journals Online and Embase), using search terms (prevalence, encephalocele, “neural tube defects”, “cranium bifidum”, “congenital malformations”, “congenital defects”, “structural birth defects”, “structural abnormalities”, newborns/neonates/ “live births”/ “stillbirths” and their MeSH Terms) up to 16 July 2021. The JBI quality appraisal checklist was used to assess the quality of studies when they were abstracted using a standardised data extraction template. The I² statistic and Cochrane Q test were used to examine heterogeneity across studies statistically. The prevalence of encephalocele was estimated using a random-effect meta-analysis model. Subgroup, sensitivity, meta-regression and time trend analysis were carried out. The publication bias was checked using Egger and Begg’s tests.

Results

Twenty-seven relevant studies were identified and provided a total of 5 107 109 births. In this systematic review and meta-analysis, the pooled birth prevalence of encephalocele in Africa was 0.02% (or 2 per 10 000 births) (95% CI 0.02% to 0.03%). The overall prevalence of birth encephalocele using the median from studies was 0.02% (IQR=0.01%–0.04%). Higher prevalence of encephalocele was detected in Nigeria 0.06% (95% CI 0.04% to 0.08%), Sudan 0.04% (95% CI 0.03% to 0.05%), Egypt 0.04% (95% CI 0.04% to 0.05%), DR of Congo 0.02% (95% CI 0.02% to 0.03%), Ethiopia 0.02% (95% CI −0.004% to 0.05%) and Tanzania 0.02% (95% CI 0.002% to 0.04%). The prevalence of encephalocele per live birth was 0.03% and both live birth and stillbirth was 0.03%.

Conclusions

This review indicates a high prevalence of encephalocele, but studies were limited suggesting the need for additional research.

PROSPERO registration number

CRD42021242161.

Hydrocephalus and occipital encephaloceles: presentation of a series and review of the literature

INTRODUCTION

Encephaloceles are rare congenital malformations of the central nervous system in which brain tissue is extruded from a defect in the skull. Hydrocephalus can occur in 60 to 90% of patients with posterior encephaloceles when compared to other types of this malformation. This article aims to present a series of posterior encephaloceles and its association with hydrocephalus as well as promote a review of the pertinent literature.

MATERIAL AND METHODS

A retrospective study of our series based on hospital charts of 50 patients with posterior encephaloceles was performed. Data on sex, location of encephalocele, presence of associated malformations, presence of neural tissue within the malformation, presence of hydrocephalus and microcephaly were recorded.

RESULTS

There were 29 females and 21 males. There were 25 (50%) supratorcular, 8 (16%) torcular, and 17 (34%) infratorcular lesions. Mean age of encephalocele primary repair was 8 days (range 2-120 days). Hydrocephalus was diagnosed in 25 (50%) of the cases. Ventriculoperitoneal shunt was inserted in 24 patients. The mean age at VP shunt insertion was 1.3 months (range 0.3-9 months). Endoscopic third ventriculostomy was successfully performed in one patient. Dandy-Walker malformation and ventriculomegaly prior to encephalocele surgical correction were positively associated with hydrocephalus (p values 0.05 and 0.01, respectively). Chiari III malformation was found in 2 cases, both requiring CSF shunt for treatment of hydrocephalus and are stable in follow-up. Microcephaly was present in 9 cases. The known mortality rate was 8%.

CONCLUSIONS

Hydrocephalus is common in patients with posterior encephaloceles, being more frequent in the supratorcular type, especially when associated to Dandy-Walker, Chiari III malformation, and pre-existing ventriculomegaly. The severity of giant encephaloceles, when associated to torcular types and microcephaly, is a limiting factor for development of hydrocephalus, due both to the rapid evolution of natural history and the structural changes in microcephaly.

Gene Environment Interactions in the Etiology of Neural Tube Defects

Human structural congenital malformations are the leading cause of infant mortality in the United States. Estimates from the United States Center for Disease Control and Prevention (CDC) determine that close to 3% of all United States newborns present with birth defects; the worldwide estimate approaches 6% of infants presenting with congenital anomalies. The scientific community has recognized for decades that the majority of birth defects have undetermined etiologies, although we propose that environmental agents interacting with inherited susceptibility genes are the major contributing factors. Neural tube defects (NTDs) are among the most prevalent human birth defects and as such, these malformations will be the primary focus of this review. NTDs result from failures in embryonic central nervous system development and are classified by their anatomical locations. Defects in the posterior portion of the neural tube are referred to as meningomyeloceles (spina bifida), while the more anterior defects are differentiated as anencephaly, encephalocele, or iniencephaly. Craniorachischisis involves a failure of the neural folds to elevate and thus disrupt the entire length of the neural tube. Worldwide NTDs have a prevalence of approximately 18.6 per 10,000 live births. It is widely believed that genetic factors are responsible for some 70% of NTDs, while the intrauterine environment tips the balance toward neurulation failure in at risk individuals. Despite aggressive educational campaigns to inform the public about folic acid supplementation and the benefits of providing mandatory folic acid food fortification in the United States, NTDs still affect up to 2,300 United States births annually and some 166,000 spina bifida patients currently live in the United States, more than half of whom are now adults. Within the context of this review, we will consider the role of maternal nutritional status (deficiency states involving B vitamins and one carbon analytes) and the potential modifiers of NTD risk beyond folic acid. There are several well-established human teratogens that contribute to the population burden of NTDs, including: industrial waste and pollutants [e.g., arsenic, pesticides, and polycyclic aromatic hydrocarbons (PAHs)], pharmaceuticals (e.g., anti-epileptic medications), and maternal hyperthermia during the first trimester. Animal models for these teratogens are described with attention focused on valproic acid (VPA; Depakote). Genetic interrogation of model systems involving VPA will be used as a model approach to discerning susceptibility factors that define the gene-environment interactions contributing to the etiology of NTDs.

A case report of confusing meningoencephalocele

The clinical approach plays a pivotal role in neonates with evidence of a skull mass, together with the need of monitoring unclear cases. Indeed, apparently transient alterations of the skull may be neural tube defects, which need prompt treatment.

Comparison of inherited neural tube defects in companion animals and livestock

Neural tube defects (NTDs) are congenital malformations resulting from the improper or incomplete closure of the neural tube during embryonic development. A number of similar malformations of the protective coverings surrounding the central nervous system are also often included under this umbrella term, which may not strictly fit this definition. A range of NTD phenotypes exist and have been reported in humans and a wide range of domestic and livestock species. In the veterinary literature, these include cases of anencephaly, encephalocele, dermoid sinus, spina bifida, and craniorachischisis. While environmental factors have a role, genetic predisposition may account for a significant part of the risk of NTDs in these animal cases. Studies of laboratory model species (fish, birds, amphibians, and rodents) have been instrumental in improving our understanding of the neurulation process. In mice, over 200 genes that may be involved in this process have been identified and variant phenotypes investigated. Like laboratory mouse models, domestic animals and livestock species display a wide range of NTD phenotypes. They remain, however, a largely underutilized population and could complement already established laboratory models. Here we review reports of NTDs in companion animals and livestock, and compare these to other animal species and human cases. We aim to highlight the potential of nonlaboratory animal models for mutation discovery as well as general insights into the mechanisms of neurulation and the development of NTDs.

Caffeine exposure during pregnancy: Is it safe?

Numerous studies have examined the association between maternal caffeine consumption and infant and childhood health outcomes and the results have been inconsistent. The study of maternal caffeine intake and infant and childhood health outcomes is prone to methodologic challenges. In this review, we examine the existing evidence juxtaposed with the epidemiologic design challenges that color the interpretation of the study results presented. In light of methodologic/interpretation challenges, it seems reasonable to infer that exposure to low levels of caffeine is probably not associated with substantial infant and childhood adversities. However, more research is needed using well designed studies that address methodologic challenges.

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.

Management of median and paramedian craniofacial clefts

BACKGROUND

Median and paramedian craniofacial clefts are associated with hypertelorism, anterior encephalocele, positional abnormalities of the maxilla, and nasal deformity. Cleft lip and palate, eyelid coloboma, and widow's peak are frequently present.

METHODS

The authors collected data from 30 patients (mean age, 5.8 years; range, 4 months to 18 years) operated between 1986 and 2017 with median or paramedian craniofacial clefts of differing degrees of severity. Malformations of the different anatomic units and their surgical treatment were assessed, as well as complication rates.

RESULTS

All patients presented nasal malformations and either telecanthus (n = 16) or hypertelorism (n = 14). Most patients (n = 23) had anterior encephalocele. All patients underwent nasal corrections, and most of them had medial canthopexy (n = 24). Excision of encephalocele was associated with fronto-orbital remodeling. Medialization of the orbits was performed in 11 patients, mainly by box shift (n = 9). Patients from outside Switzerland (n = 23) were operated at an older age than those in the native patient group. Because of staged reconstruction, 13 patients had more than one operation. Surgical complications included three infections and one expander exposition. One patient had bone resorption of a frontal bone flap. Nasal correction needed more than one procedure in 5 patients, and medial canthopexy had to be repeated in 7 patients. Esthetic results were satisfactory, permitting social integration.

CONCLUSION

Median and paramedian craniofacial clefts need adapted and carefully planned corrections respecting the growth of anatomic units. The quality of the medial canthal and nasal reconstruction is to a large extent responsible for the overall result.

Frontoethmoidal encephalocele: clinical presentation, diagnosis, treatment, and complications in 400 cases

PURPOSE

The purpose of this study is to review a large series of frontoethmoidal encephalocele (FEE) regarding their clinical presentation, the progressiveness of the mass volume, the skin stigmata as well as its surgical approach and post-surgical complications.

METHOD

Records of all FEE patients treated in Soetomo General Hospital, Surabaya, and Charity Foundation Program from 2008 to 2015 were reviewed. Detailed patient's demography, clinical findings, radiology results, operative procedures, and complications were documented. Follow-up was organized in weekly basis for the first 1 month after surgery or more often when situation or complication occurred. Wound healing, neurological assessment for new or progressive deficit, pseudomeningocele, skin breakdown, cerebrospinal fluid (CSF) leakage, exposed implant, recurrent mass, and cosmetic results were documented. Since most of the patients had no direct phone line at their hometown, we relied on social worker to contact them.

RESULTS

One-stage surgery was performed for 400 patients with FEE (212 were male and 188 were female). Of 400 patients, 388 (97%) were younger than 18 years old. Most FEEs were nasoethmoidal, either isolated or combined with nasoorbital type (347 cases [86.75%]); nasofrontal subtypes were seen in 34 cases (8.5%) and nasoorbital in 14 cases (1.5%). The mean operative time was 2 h (range 30 min-3 h). There were only two patients (0.5%) needed postoperative blood transfusions. Mean hospitalization time was 5 days (range 4-7 days). Overall, complication rate in our series was 12.5%, mostly was CSF leakage and wound dehiscence.

CONCLUSION

The current socioeconomic conditions and local facility should be considered to treat these specific disease processes. The refined and meticulous technique, especially in choosing the approach and handling the dural closure, is essential in lowering the complication rate.

Neurosurgical Interventions for Occipital Encephalocele

Aims and Objectives:

The aim of this study is to find the outcome of repair and resection of the occipital encephalocele.

Study Design:

Case series.

Materials and Methods:

The clinical data of fifty consecutive occipital encephalocele patients were retrieved from medical records including operative notes, postoperative follow-up visits, and postsurgical complications were noted for analysis from November 2009 to November 2013 at the Department of Neurosurgery, Jinnah Postgraduate Medical Centre, Karachi, Pakistan. All patients were assessed by computed tomography scan, magnetic resonance imaging brain, and ultrasound when needed. Physician's assessment, physical examination, and his/her questions to the family at follow-up were used as a tool to determine if there was a developmental delay rather than quantitative analysis like hydrocephalus questionnaires. Patients who developed complications and delayed milestone were regarded as no improvement and those who did not develop complications and achieved appropriate milestone were regarded as improved at 18 months follow-up.

Results:

Of 50 patients, 17 were males and 33 were females. The average age at presentation was 2.4 months. 16 (32%) patients had increased head circumference and hydrocephalus, 2 (4%) had associated Dandy–Walker cyst, 3 (6%) developed developmental delays, and 8 (15%) had a seizure disorder. None of our patients had neurological deficits. The size of the sac ranged from 2 cm × 3 cm to 27 cm × 15 cm. 9 (18%) patients were admitted with the complication of sac rupture and 2 (4%) patients sac ruptured after admission. Only one patient (2%) had a cerebrospinal fluid leak postoperatively that was repaired primarily without patch graft or dura seal while 4 (8%) developed hydrocephalus after repair of the sac which was treated with placement of ventriculoperitoneal shunt. One (2%) patient did not recover from anesthesia and expired.

Conclusion:

Encephalocele is commonly seen in the practice of neurosurgery in the world as well as in Pakistan. Modern neuroimaging, neurosurgical techniques, and neonatal neurological intensive care have greatly improved morbidity and mortality in the care of encephalocele.

Surgical resection of large encephalocele: a report of two cases and consideration of resectability based on developmental morphology

INTRODUCTION

The first-line treatment of encephalocele is reduction of herniated structures. Large irreducible encephalocele entails resection of the lesion. In such case, it is essential to ascertain preoperatively if the herniated structure encloses critical venous drainage.

CASE REPORTS

Two cases of encephalocele presenting with large occipital mass underwent magnetic resonance (MR) imaging. In first case, the skin mass enclosed the broad space containing cerebrospinal fluid and a part of occipital lobe and cerebellum. The second case had occipital mass harboring a large portion of cerebrum enclosing dilated ventricular space. Both cases had common venous anomalies such as split superior sagittal sinus and high-positioned torcular herophili. They underwent resection of encephalocele without subsequent venous congestion. We could explain the pattern of venous anomalies in encephalocele based on normal developmental theory.

CONCLUSION

Developmental theory connotes that major dural sinuses cannot herniate into the sac of encephalocele. Irrespective to its size, encephalocele can be resected safely at the neck without subsequent venous congestion.

ASPP2 deficiency causes features of 1q41q42 microdeletion syndrome

Chromosomal abnormalities are implicated in a substantial number of human developmental syndromes, but for many such disorders little is known about the causative genes. The recently described 1q41q42 microdeletion syndrome is characterized by characteristic dysmorphic features, intellectual disability and brain morphological abnormalities, but the precise genetic basis for these abnormalities remains unknown. Here, our detailed analysis of the genetic abnormalities of 1q41q42 microdeletion cases identified TP53BP2, which encodes apoptosis-stimulating protein of p53 2 (ASPP2), as a candidate gene for brain abnormalities. Consistent with this, Trp53bp2-deficient mice show dilation of lateral ventricles resembling the phenotype of 1q41q42 microdeletion patients. Trp53bp2 deficiency causes 100% neonatal lethality in the C57BL/6 background associated with a high incidence of neural tube defects and a range of developmental abnormalities such as congenital heart defects, coloboma, microphthalmia, urogenital and craniofacial abnormalities. Interestingly, abnormalities show a high degree of overlap with 1q41q42 microdeletion-associated abnormalities. These findings identify TP53BP2 as a strong candidate causative gene for central nervous system (CNS) defects in 1q41q42 microdeletion syndrome, and open new avenues for investigation of the mechanisms underlying CNS abnormalities.

Impact of Periconceptional Use of Nitrosatable Drugs on the Risk of Neural Tube Defects

Nitrosatable drugs (NSDs) can, in the presence of nitrosating agents and highly acidic conditions, form N-nitroso compounds that have been found to be teratogenic in animal models. Using data from the Slone Epidemiology Center Birth Defects Study collected from 1998 to 2012, we compared maternal periconceptional NSD use between 334 neural tube defect cases and 7,619 nonmalformed controls. We categorized NSDs according to their functional group (secondary amine, tertiary amine, and amide). With logistic regression models, we estimated adjusted odds ratios and 95% confidence intervals. Neural tube defect risk was associated with maternal periconceptional use of secondary (adjusted odds ratio (aOR) = 1.7, 95% confidence interval (CI): 1.1, 2.4) and tertiary (aOR = 1.7, 95% CI: 1.2, 2.5) amines; an association was observed for amides, but the 95% confidence interval included the null (aOR = 1.4, 95% CI: 0.7, 2.5). Within the secondary amine group, elevated adjusted odds ratios were observed for 3 drugs but were null for the remaining medications. Increases in risk were observed for both strata of folic acid intake (<400 µg/day, ≥400 µg/day), with a slightly higher risk in the ≥400-µg/day stratum. Our findings support previously reported positive associations between neural tube defects and periconceptional exposure to NSDs containing a secondary or tertiary amine or amide.

Risk factors for hydrocephalus and neurological deficit in children born with an encephalocele

OBJECT

There is a known association of hydrocephalus with encephaloceles. Risk factors for hydrocephalus and neurological deficit were ascertained in a series of patients born with an encephalocele.

METHODS

A retrospective analysis was undertaken of patients treated for encephaloceles at Children's Hospital Los Angeles between 1994 and 2012. The following factors were evaluated for their prognostic value: age at presentation, sex, location of encephalocele, size, contents, microcephaly, presence of hydrocephalus, CSF leak, associated cranial anomalies, and neurological outcome.

RESULTS

Seventy children were identified, including 38 girls and 32 boys. The median age at presentation was 2 months. The mean follow-up duration was 3.7 years. Encephalocele location was classified as anterior (n = 14) or posterior (n = 56) to the coronal suture. The average maximum encephalocele diameter was 4 cm (range 0.5-23 cm). Forty-seven encephaloceles contained neural tissue. Eight infants presented at birth with CSF leaking from the encephalocele, with 1 being infected. Six patients presented with hydrocephalus, while 11 developed progressive hydrocephalus postoperatively. On univariate analysis, the presence of neural tissue, cranial anomalies, encephalocele size of at least 2 cm, seizure disorder, and microcephaly were each positively associated with hydrocephalus. On multivariate logistic regression modeling, the single prognostic factor for hydrocephalus of borderline statistical significance was the presence of neural tissue (odds ratio [OR] = 5.8, 95% confidence interval [CI] = 0.8-74.0). Fourteen patients had severe developmental delay, 28 had mild/moderate delay, and 28 were neurologically normal. On univariate analysis, the presence of cranial anomalies, larger size of encephalocele, hydrocephalus, and microcephaly were positively associated with neurological deficit. In the multivariable model, the only statistically significant prognostic factor for neurological deficit was presence of hydrocephalus (OR 17.2, 95% CI 1.7-infinity).

CONCLUSIONS

In multivariate models, the presence of neural tissue was borderline significantly associated with hydrocephalus and the presence of hydrocephalus was significantly associated with neurological deficit. The location of the encephalocele did not have a statistically significant association with incidence of hydrocephalus or neurological deficit. In contrast to modestly good/fair neurological outcome in children with an encephalocele without hydrocephalus, the presence of hydrocephalus resulted in a far worse neurological outcome.

Myelomeningocele (open spina bifida) - surgical management

Myelomeningocele has been recognized since ancient times although written descriptions began not before the 17th century. Among all serious congenital malformations, myelomeningocele is unique that is has a steady and considerable prevalence while being compatible with life. It has a dismal prognosis when left untreated where virtually all die within the first year while aggressive treatment have a profound effect on survival and quality of life. Effective surgical treatment became possible parallel to the treatment of hydrocephalus in the late 1950s. Advent of the shunt systems undoubtedly changed the morbidity and mortality rates due to associated hydrocephalus. Aggressive and effective treatment improved survival rates but also those suffering physical and mental disabilities have increased as well. Ethical and socioeconomic concerns have led to proposal for selective treatment criteria which have raised arguments on medical and ethico-legal rounds. After the swing of the pendulum between early treatment in all affected children and selective treatment of those who fulfilled the criteria for good prognosis, early myelomeningocele repair is practiced widely unless the infant is critically ill.Incidence of myelomeningocele has been decreasing especially in the Western world, partly due to prenatal diagnosis and elective terminations, dietary folate supplementation. Still, it is the most common central nervous system malformation and one of the leading causes of paraplegia, worldwide. Unfortunately, gains in the management of myelomeningocele have been mainly on antenatal diagnosis and prevention while efforts on understanding its cause, mechanisms involved are still tentative. Concerning the surgical management, no revolutionary modification improving outcome has been introduced unlike other fields of neurosurgery.Medical management of a child with myelomeningocele requires a lifelong effort of several disciplines including urology, orthopedics physical and social therapy besides neurosurgery. The initial and probably the most crucial step begin with proper repair of the lesion. The aim of surgery, with its simplest definition should be towards maintaining the medical condition of the newborn. In other words, consequences of an open spinal cord segment with associated malformations have to be avoided with appropriate measures. Comparable to the surgical treatment of any congenital malformation, myelomeningocele repair consist of reversing the failed steps of normal neural tube closure. This requires a thorough understanding of the normal and abnormal embryological sequence of events in formation of the spinal cord. Although the purpose of this chapter is to describe the basic concepts and technique of myelomeningocele repair, contemporary information and progress on epidemiology, and etiology and embryology is presented with discussion of controversial issues regarding the selection process, optimal time for surgery and technical modifications.

Prenatal imaging of occipital encephaloceles

INTRODUCTION

This retrospective study aims to describe systematically the fetal cerebral MR morphology in cases with occipital meningoencephaloceles using standard and advanced fetal MRI techniques.

MATERIAL AND METHODS

The 1.5-tesla MR examinations (T1- and T2-weighted imaging, echo planar imaging, EPI, diffusion-weighted imaging, DWI) of 14 fetuses with occipital/parietal meningoencephaloceles were retrospectively analyzed for the classification of anatomic characteristics. A diffusion tensor sequence was performed in 5 cases.

RESULTS

In 9/14 cases the occipital lobes were entirely or partially included in the encephalocele sac. Typical features of Chiari III malformation were seen in 6/14 cases. The displaced brain appeared grossly disorganized in 6/14. The brainstem displayed abnormal 'kinking'/rotation (3/14), a z-shape (1/14) and/or a molar tooth-like configuration of the midbrain (3/14). Tractography revealed the presence and position of sensorimotor tracts in 5/5 and the corpus callosum in 3/5. DWI was helpful in the identification of a displaced brain (in 8/9). EPI visualized the anatomy of draining cerebral veins in 7/9 cases. Clinical (9/14) and MRI (7/14) follow-up data are presented.

DISCUSSION

Encephaloceles show a wide range of morphological heterogeneity. Fetal MRI serves as an accurate tool in the visualization of brainstem, white matter pathway and cerebral venous involvement and facilitates the detection of specific underlying syndromes such as ciliopathies.

Midline craniofacial malformations with a lipomatous cephalocele are associated with insufficient closure of the neural tube in the tuft mouse

BACKGROUND

Genetic variations affecting neural tube closure along the head result in malformations to the face and brain, posing a significant impact on health care costs and the quality of life.

METHODS

We have established a mouse line from a mutation that arose spontaneously in our wild-type colony that we called tuft. Tuft mice have heritable midline craniofacial defects featuring an anterior lipomatous cephalocele.

RESULTS

Whole-mount skeletal stains indicated that affected newborns had a broader interfrontal suture where the cephalocele emerged between the frontal bones. Mice with a cephalocele positioned near the rostrum also presented craniofacial malformations such as ocular hypertelorism and midfacial cleft of the nose. Gross and histological examination revealed that the lipomatous cephalocele originated as a fluid filled cyst no earlier than E14.5 while embryos with a midfacial cleft was evident during craniofacial development at E11.5. Histological sections of embryos with a midfacial cleft revealed the cephalic neuroectoderm remained proximal or fused to the frontonasal ectoderm about the closure site of the anterior neuropore, indicating a defect to neural tube closure. We found the neural folds along the rostrum of E9 to E10.5 embryos curled inward and failed to close as well as embryos with exencephaly and anencephaly at later stages. Whole-mount in situ hybridization of anterior markers Fgf8 and Sonic hedgehog indicated closure of the rostral site was compromised in severe cases.

CONCLUSION

We present a model demonstrating how anterior cranial cephaloceles are generated following a defect to neural tube closure and relevance to subsequent craniofacial morphogenesis in the tuft mouse.

Birth prevalence of neural tube defects: a population-based study in South-Eastern Hungary

PURPOSE

Primary prevention by periconceptional folic acid supplementation can significantly reduce the risk of neural tube defects. EUROCAT, the European network of population-based registries for the epidemiologic surveillance of congenital anomalies, lacks sufficient data on the birth prevalence of neural tube defects in Hungary before and after the promotion of primary prevention by folic acid. Our aims were to compare the birth prevalence of neural tube defects (myelomeningocele, anencephaly and encephalocele) over two 12-year periods in South-Eastern Hungary. Further aims were to compare our data to those ones in other areas in Europe.

METHODS

Data were collected from the databases of the Department of Hungarian Congenital Abnormality Registry. The total and live birth prevalence rate of neural tube defects were calculated and compared over 1980-1991 and 1994-2005. In addition, the trends in the total birth prevalence, the number of live births and terminations for and stillbirths with neural tube defects were analysed throughout the period of 1994-2005.

RESULTS

A significant decline was found in the total and live birth prevalence of myelomeningocele, anencephaly and encephalocele over 1994-2005 compared to the period of 1980-1991. The total birth prevalence of neural tube defects, however, showed a trend of increase after 1994, with declining number of live births and increasing number of terminations for neural tube defects.

CONCLUSION

Public health measures are warranted in order to replace termination of pregnancy with primary prevention in South-Eastern Hungary.

Working towards a risk prediction model for neural tube defects

BACKGROUND

Several risk factors have been consistently associated with neural tube defects (NTDs). However, the predictive ability of these risk factors in combination has not been evaluated.

METHODS

To assess the predictive ability of established risk factors for NTDs, we built predictive models using data from the National Birth Defects Prevention Study, which is a large, population-based study of nonsyndromic birth defects. Cases with spina bifida or anencephaly, or both (n = 1239), and controls (n = 8494) were randomly divided into separate training (75% of cases and controls) and validation (remaining 25%) samples. Multivariable logistic regression models were constructed with the training samples. The predictive ability of these models was evaluated in the validation samples by assessing the area under the receiver operator characteristic curves. An ordinal predictive risk index was also constructed and evaluated. In addition, the ability of classification and regression tree (CART) analysis to identify subgroups of women at increased risk for NTDs in offspring was evaluated.

RESULTS

The predictive ability of the multivariable models was poor (area under the receiver operating curve: 0.55 for spina bifida only, 0.59 for anencephaly only, and 0.56 for anencephaly and spina bifida combined). The predictive abilities of the ordinal risk indexes and CART models were also low.

CONCLUSION

Current established risk factors for NTDs are insufficient for population-level prediction of a women's risk for having affected offspring. Identification of genetic risk factors and novel nongenetic risk factors will be critical to establishing models, with good predictive ability, for NTDs.

Lateral posterior fossa encephalocele with associated migrational disorder of the cerebellum in an infant

Encephaloceles are acquired or congenital defects in which intracranial contents protrude through a defect in the calvaria. The embryogenesis of these lesions is incompletely understood. The vast majority of lesions occur at or near the anatomical midline. The authors present an extremely rare case of a laterally oriented, pathologically proven encephalocele associated with a posterior fossa cyst and cerebellar migrational defect in an infant. The authors review past and current theories of encephalocele formation as it relates to this case.

Diagnosis and management of cephaloceles

Cephaloceles are rare neural tube defects. In this study, we retrospectively reviewed the charts of all patients with cephaloceles who underwent surgical treatment in our institute for a 14-year period, between January 1995 and January 2009. There were 27 children (11 boys and 16 girls; mean age, 7.5 mo; range, 1 d to 7 y). Seventeen encephaloceles were occipital; 5, parietal; 2, ethmoidal; 1, frontoethmoidal; 1, nasoethmoidal; and 1, sphenoethmoidal. The mean size of sac was 3 cm, although 2 cases of giant occipital encephaloceles were observed. In 19 cases (70%), the sac contained gliotic brain (encephaloceles) that was excised. All patients were operated on in 1 surgical procedure. Hydrocephalus was found in 16 patients and treated with a ventriculoperitoneal shunt insertion. Postoperatively, there was no neurologic deficit or death. After a mean follow-up period of 7.2 years (range, 6 mo to 11.5 y), all patients were in good condition. In conclusion, occipital cephaloceles are more frequently encountered and are usually associated with hydrocephalus. Surgery should be performed as early as possible and only after careful preoperative planning especially for the anterior cephaloceles.

Importance of including all pregnancy outcomes to reduce bias in epidemiologic studies of neural tube defects--Texas, 1999 to 2005

BACKGROUND

Neural tube defects (NTDs) often result in fetal death or elective termination; therefore, not all cases are captured in typical hospital-based surveillance. We examined sociodemographic differences among pregnancy outcomes to assess sources of bias in NTD surveillance and research.

METHODS

We used 1999 to 2005 Texas Birth Defects Registry data, a population-based active surveillance system, and calculated crude and adjusted prevalence ratios (aPRs). We then assessed the association of anencephaly and spina bifida with the selected characteristics, stratified by pregnancy outcomes (fetal death, elective termination, or live birth).

RESULTS

Data were available for 1852 NTD cases (anencephaly, 677; spina bifida, 954; and encephalocele, 221), resulting in 1211 live births, 236 fetal deaths, and 405 elective terminations. For both anencephaly and spina bifida, a significant excess of Hispanic mothers was observed among live-birth cases (aPRs=1.2-2.4), but not among mothers experiencing other pregnancy outcomes. Mothers of anencephaly cases resulting in a non-live birth were more likely to be adolescents (aPRs=2.4-2.7 for ages<20 years old vs. ages 25-29 years old), but this pattern was not observed for live-birth cases. A trend of increasing anencephaly risk with increasing parity was demonstrated only among fetal-death cases. For spina bifida, mothers of fetal-death (but not live-birth) cases were less likely to live along the Texas-Mexico border (aPR=0.30).

CONCLUSIONS

Demographic differences across NTD pregnancy outcomes exist and are a potential source of bias. Inclusion of all pregnancy outcomes in NTD surveillance is vital in NTD monitoring and research.

Congenital spinal tumor in a patient with encephalocele and hydrocephalus: a case report

Introduction

Encephalocele is a rare congenital abnormality of the central nervous system, where brain tissue protrudes from a defect in the skull. Some anomalies are associated with encephalocele. However, the association of spinal teratoma and encephalocele has not been reported in the English literature.

Case presentation

We report the case of an Iranian girl with a history of encephalocele surgery, who, at the age of four years, developed an intramedullary spinal teratoma, and discuss the pathogenesis of this association.

Conclusion

To the best of our knowledge, this is the first report of an association between encephalocele and spinal teratoma.

An update to the list of mouse mutants with neural tube closure defects and advances toward a complete genetic perspective of neural tube closure

The number of mouse mutants and strains with neural tube defects (NTDs) now exceeds 240, including 205 representing specific genes, 30 for unidentified genes, and 9 multifactorial strains. These mutants identify genes needed for embryonic neural tube closure. Reports of 50 new NTD mutants since our 2007 review (Harris and Juriloff, 2007) were considered in relation to the previously reviewed mutants to obtain new insights into mechanisms of NTD etiology. In addition to null mutations, some are hypomorphs or conditional mutants. Some mutations do not cause NTDs on their own, but do so in digenic, trigenic, and oligogenic combinations, an etiology that likely parallels the nature of genetic etiology of human NTDs. Mutants that have only exencephaly are fourfold more frequent than those that have spina bifida aperta with or without exencephaly. Many diverse cellular functions and biochemical pathways are involved; the NTD mutants draw new attention to chromatin modification (epigenetics), the protease-activated receptor cascade, and the ciliopathies. Few mutants directly involve folate metabolism. Prevention of NTDs by maternal folate supplementation has been tested in 13 mutants and reduces NTD frequency in six diverse mutants. Inositol reduces spina bifida aperta frequency in the curly tail mutant, and three new mutants involve inositol metabolism. The many NTD mutants are the foundation for a future complete genetic understanding of the processes of neural fold elevation and fusion along mechanistically distinct cranial-caudal segments of the neural tube, and they point to several candidate processes for study in human NTD etiology.

Polytomous logistic regression as a tool for exploring heterogeneity across birth defect subtypes: an example using anencephaly and spina bifida

BACKGROUND

In birth defect epidemiology, phenotypic subgroups are often combined into a composite phenotype in an effort to increase statistical power. Although the validity of using composite phenotypes has been questioned, formal evaluations of the underlying assumption of effect homogeneity across component phenotypes have not been conducted.

METHODS

Polytomous logistic regression was used to assess effect heterogeneity of several generally accepted neural tube defect (NTD) risk factors across the component phenotypes of anencephaly and spina bifida. Data for these analyses were obtained from the National Birth Defects Prevention Study.

RESULTS

The use of a composite phenotype has the potential to mask associations specific to a component phenotype and in some cases the effect of a variable may be misattributed to the composite phenotype. For example, an association between infant sex and anencephaly (adjusted odds ratio [AOR], 1.5; 95% CI, 1.1-1.9) was masked when data from all NTDs were analyzed (AOR, 1.1; 95% CI, 0.9-1.3), whereas an association with maternal body mass index that was specific to spina bifida (AOR, 1.9; 95% CI, 1.6-2.4) was attributed to all NTDs (AOR, 1.6; 95% CI, 1.4-2.0). Furthermore, conclusions regarding effect heterogeneity based on ad hoc comparisons, rather than some formal assessment, may be vulnerable to considerable subjectivity, as was the case for the association of maternal Hispanic ethnicity with spina bifida (AOR, 1.4; 95% CI, 1.2-1.8) and anencephaly (AOR, 2.0; 95% CI, 1.5-2.8).

CONCLUSIONS

Polytomous logistic regression provides a useful tool for evaluating putative risk factors for which there is no a priori basis for assuming effect homogeneity across component phenotypes.

Congenital duplication of the superior sagittal sinus and parietal encephalocele after vacuum extraction delivery

A newly-born infant with a congenital dural and bony defect and an associated short-segmented duplication of the superior sagittal sinus suffered from herniation and infarction of parietal brain tissue secondary to vacuum extraction. This ultimately led to the formation of a subgaleal cerebrospinal fluid (CSF) collection. Initial operative closure of the encephalocele was performed by attaching a galeal flap to the periostium surrounding the congenital defect. As the bony defect developed characteristics of a growing fracture later on, dural repair, transplantation of a split-bone flap and, finally, the insertion of a ventriculoperitoneal shunt became necessary. This case affirms that stringent indication and cautious usage of vacuum-assisted delivery is strongly recommended, especially in view of the possibility that undetected congenital cranial, vascular and/or cerebral alterations may be present.

Maternal dietary glycemic intake and the risk of neural tube defects

Both maternal diabetes and obesity have been associated with an increased risk of neural tube defects (NTD), possibly due to a sustained state of hyperglycemia and/or hyperinsulinemia. Data were collected in the Boston University Slone Birth Defects Study (a case-control study) from 1988 to 1998. The authors examined whether high dietary glycemic index (DGI) and high dietary glycemic load (DGL) increased the risk of NTDs in nondiabetic women. Mothers of NTD cases and nonmalformed controls were interviewed in person within 6 months after delivery about diet and other exposures. Odds ratios and 95% confidence intervals were estimated from logistic regression for high DGI (> or =60) and high DGL (> or =205), with cutpoints determined by cubic spline. Of 698 case mothers, 25% had high DGI and 4% had high DGL. Of 696 control mothers, 15% had high DGI and 2% had high DGL. After adjustment for sociodemographic factors and other dietary factors, the odds ratio for high DGI was 1.5 (95% confidence interval: 1.1, 2.0); for high DGL, it was 1.8 (95% confidence interval: 0.8, 4.0). Diets with proportionally high DGI or DGL may put the developing fetus at risk of an NTD, adding further evidence that hyperglycemia lies within the pathogenic pathway.

Cost-effectiveness of mandatory folate fortification v. other options for the prevention of neural tube defects: results from Australia and New Zealand

OBJECTIVE

To provide input to Australian and New Zealand government decision making regarding an optimal strategy to reduce the rate of neural tube defects (NTD).

DESIGN

Standard comparative health economic evaluation techniques were employed for a set of intervention options for promoting folate/folic acid consumption in women capable of or planning a pregnancy. Evidence of effectiveness was informed by the international literature and costs were derived for Australia and New Zealand.

RESULTS

Population-wide campaigns to promote supplement use and mandatory fortification were the most effective at reducing NTD, at an estimated 36 and 31 fewer cases per annum respectively for Australia and New Zealand, representing an 8 % reduction in the current annual NTD rate. Population-wide and targeted approaches to increase supplement use were cost-effective, at less than $AU 12,500 per disability-adjusted life year (DALY) averted ($US 9893, pound 5074), as was extending voluntary fortification. Mandatory fortification was not cost-effective for New Zealand at $AU 138,500 per DALY ($US 109 609, pound 56,216), with results uncertain for Australia, given widely varying cost estimates. Promoting a folate-rich diet was least cost-effective, with benefits restricted to impact on NTD.

CONCLUSIONS

Several options for reducing NTD appear to fall well within accepted societal cost-effectiveness norms. All estimates are subject to considerable uncertainty, exacerbated by possible interactions between interventions, including impacts on currently effective strategies. The Australian and New Zealand governments have decided to proceed with mandatory fortification; it is hoped they will support a rigorous evaluation which will contribute to the evidence base.

Risk factors associated with occipital encephalocele: a case-control study. Clinical article

OBJECT

An encephalocele is characterized by congenital herniation of the brain tissue and/or meninges through a skull defect. The underlying cause is complex and not fully understood, but environmental agents are suspected. The authors aimed to determine the known risk factors for encephaloceles.

METHODS

Potential risk factors were studied in 31 children with encephaloceles who had been referred to the outpatient clinic. At the same time, 31 children with non-CNS anomalies were randomly selected from the same hospital as a control group. Both cohorts were assessed in person through interviews with the mothers.

RESULTS

Most children with encephaloceles were female. There was no significant risk factor in the case group as compared with controls, although the families of patients with encephaloceles had a better economic status (p=0.03) and the fathers had a higher mean age.

CONCLUSIONS

Although the authors of this study could not identify any significant risk factors for encephaloceles, environmental factors can still be mentioned as probable etiological elements. Additional studies with larger sample sizes and more comprehensive evaluations are required to confirm the role of environmental or genetic factors to prevent the occurrence of encephaloceles.

Urban-rural residence and the occurrence of neural tube defects in Texas, 1999-2003

Neural tube birth defects (NTDs) affect more than 4000 pregnancies in the US annually. The etiology of NTDs is believed to be multifactorial, but much remains unknown. We examined the pattern and magnitude of urban-rural variation in anencephaly, spina bifida without anencephaly, and encephalocele in Texas in relation with urban-rural residence for the period 1999-2003. There was no evidence that urban-rural residence was associated with changes in the rate of anencephaly or spina bifida without anencephaly in unadjusted or adjusted analyses. In contrast, rates of encephalocele were statistically significantly higher in areas classified as suburban or more rural compared to urban areas using four different urban-rural residence indicators.

Economic evaluation of a neural tube defect recurrence-prevention program

BACKGROUND

Women with a pregnancy affected by a neural tube defect (NTD) are encouraged to take folic acid prior to a subsequent pregnancy, but it is unknown whether organized attempts to identify and counsel such women to prevent recurrent NTDs are cost effective.

METHODS

Data from the South Carolina recurrence-prevention program for October 2001-September 2002 were analyzed between October 2002 and December 2003 to calculate costs. Cost-effectiveness modeling of the program during 1992-2006 was conducted during 2007. Results were calculated for three scenarios based on recurrence risk, supplement use, and the effectiveness of folic acid in preventing recurrences. For each scenario, quality-adjusted life years (QALYs) were calculated separately using prevented NTD-affected live births; prevented NTD-affected births (including fetal deaths); and all prevented NTD-affected pregnancies.

RESULTS

The prevention program cost approximately $155,000 per year in 2003 dollars to protect 35 pregnancies and prevent approximately one NTD. The direct costs associated with an NTD depend on type and outcome, but are approximately $560,000 in 2003 dollars for a live birth with spina bifida. The base-case cost-effectiveness ratio was $39,600 per QALY gained from avoided NTD-affected live births and stillbirths, and $14,700 per QALY gained from the avoidance of all NTD-affected pregnancies. The baseline NTD recurrence risk and the use of folic acid supplements by women who are at high risk for an NTD-affected pregnancy were influential parameters.

CONCLUSIONS

The South Carolina NTD recurrence-prevention program appears comparable in cost effectiveness to other preventive services. Other states might consider including NTD recurrence prevention in birth defect-prevention programs.

Birth defects in uncles and aunts from Irish families with neural tube defects

BACKGROUND

Previous studies suggested an excess of matrilineal cases of neural tube defects among distant relatives in NTD families. There is little information on patterns of heredity of other birth defects among distant relatives.

METHODS

Between 1995 and 2003, 78 nuclear families and 373 uncles and aunts were interviewed about birth defects among uncles and aunts in Irish families with an NTD.

RESULTS

Among 783 total uncles and aunts, those related through the mother had more birth defects overall than those related through the father (8.4 vs. 4.0%, p = 0.01). The excess persisted after controlling with logistic regression models for maternal and paternal age, gender of uncle/aunt, proband's NTD diagnosis, and year of birth (OR 2.52; 95% CI: 1.29, 4.91; p = 0.007). Among individual birth defects, significant excesses over expected rates were seen for spina bifida, congenital heart defects, and syndactyly.

CONCLUSIONS

This study of reported birth defects suggests that maternal uncles and aunts in Irish families have significantly more birth defects than paternal uncles and aunts. These results, if confirmed, support the hypothesis that NTD relatives carry a susceptibility to other birth defects, preferentially on the mother's side of the family, suggesting opportunities for prevention. Birth Defects Research (Part A) 2008.

Prevalence of encephalocele in Texas, 1999–2002

Encephaloceles are congenital malformations characterized by a sac-like protrusion of the brain and/or its' covering membranes through an opening in the skull. The etiology of encephalocele is considered to be complex, and in most cases the causes of this condition remain elusive. The present study was undertaken to determine the prevalence of encephalocele among deliveries to Texas residents during 1999-2002, and to identify maternal and demographic factors associated with encephalocele. Data were examined from 125 infants and fetuses with encephalocele and no identified chromosome abnormality; identified in Texas and delivered in 1999-2002. During the same period there were 1,449,943 live births. The birth prevalence of encephalocele and both crude and adjusted prevalence ratios were estimated from these data. Compared with the offspring of White women, encephaloceles were significantly more common among the offspring of Hispanic women (adjusted prevalence ratio: 1.91, 95% confidence interval (CI) 1.34-2.70). In addition, compared to the offspring of women 25-29 years of age, encephaloceles were more common among the offspring of women 20-24 years of age (adjusted prevalence ratio: 1.52, 95% CI 1.01-2.27) and those less than 20 years of age (adjusted prevalence ratio: 1.55, 95% CI 0.98-2.45). These findings add to the existing literature on the descriptive epidemiology of encephalocele.