Neural tube defects: Risk factors and preventive measures

Neural tube defects among new borns: a cross-sectional study

Background

Neural tube defects are a major public health issue that contributes significantly to morbidity and mortality, particularly in low-income countries such as Ethiopia. In Ethiopia, particularly in the study setting, there is a paucity of data on the prevalence, magnitude, and associated factors of neural tube defects. As a result, the purpose of this study was to evaluate neural tube defects and associated factors in JUMC.

Methods

This study was an institution-based cross-sectional study conducted from June to September 2021. Data was collected using a structured questionnaire adapted from previous literature. Data were analyzed using SPSS version 26 software. Logistic regression analysis was performed to assess the association between dependent and independent variables. Independent variables with a p-value < 0.05 were taken as statistically significant with neural tube defects.

Results

The prevalence of NTDs in this study was 3.6%. Preterm newborns with GA < 34 AOR 2.9(1.2-9.7), newborns with birth weight b/n 1,000-1,499 AOR 5.2(1.1-9.4), born with weight b/n 1,500-2,499 AOR 2.1(1.3-8.7), exposure to smoke AOR 2.1(1.2-8.8), radiation AOR 6.8(1.3-14.5), at least one history of abortion AOR 10.1(7.2-21.0) and mothers with AED intake AOR 5.7(2.3-18.4) were found to be associated significantly.

Conclusion

The results indicated a significant frequency of neural tube abnormalities in newborns. The use of AEDs, abortion, and radiation have all been linked to those NTD cases. Pregnant women are advised to learn more about the need of beginning prenatal care as soon as possible because the aforementioned issues will be addressed during this treatment.

A quest for genetic causes underlying signaling pathways associated with neural tube defects

Neural tube defects (NTDs) are serious congenital deformities of the nervous system that occur owing to the failure of normal neural tube closures. Genetic and non-genetic factors contribute to the etiology of neural tube defects in humans, indicating the role of gene-gene and gene-environment interaction in the occurrence and recurrence risk of neural tube defects. Several lines of genetic studies on humans and animals demonstrated the role of aberrant genes in the developmental risk of neural tube defects and also provided an understanding of the cellular and morphological programs that occur during embryonic development. Other studies observed the effects of folate and supplementation of folic acid on neural tube defects. Hence, here we review what is known to date regarding altered genes associated with specific signaling pathways resulting in NTDs, as well as highlight the role of various genetic, and non-genetic factors and their interactions that contribute to NTDs. Additionally, we also shine a light on the role of folate and cell adhesion molecules (CAMs) in neural tube defects.

Diagnosis and Treatment of Japanese Children with Neurogenic Bladder: Analysis of Data from a National Health Insurance Database

In pediatric patients with neurogenic bladder (NGB), urinary tract evaluation, early diagnosis, and individualized management are important. We aimed to clarify the current status of diagnosis and treatment of NGB in Japanese children. This descriptive, observational, retrospective cohort study using the JMDC claims database included NGB patients aged ≤17 years over a 12-month follow-up period. Of the 1065 pediatric NGB patients, 38.9% had spina bifida. Dermatological and gastrointestinal comorbidities were common in the baseline period. Renal/bladder ultrasound was a commonly performed investigation (38.3%), but urodynamics was infrequently used (3.0%). Of all the overactive bladder medications, anticholinergics were used commonly (17.9% patients), and most patients used anticholinergics alone (without combination therapy). Clean intermittent catheterization (CIC; alone or in combination with medications) was performed in 9.3% of patients, and 3.9% of patients were concomitantly treated with medications. The most common incident complication was lower urinary tract infection (18.1%), which was especially common in patients with open spina bifida (54.1%). Despite guideline recommendations, lower urinary tract dysfunction is not thoroughly evaluated. Adequate understanding of patient status is critical to optimal patient management (behavioral therapy, CIC, and medication) in clinical practice.

Pediatric Spina Bifida and Spinal Cord Injury

Pediatric spina bifida (SB) and spinal cord injury (SCI) are unfortunately common in our society, and their unique findings and comorbidities warrant special consideration. This manuscript will discuss the epidemiology, pathophysiology, prevention, and management strategies for children growing and developing with these unique neuromuscular disorders. Growth and development of the maturing child places them at high risk of spinal cord tethering, syringomyelia, ascending paralysis, pressure injuries, and orthopedic abnormalities that must be addressed frequently and judiciously. Similarly, proper neurogenic bladder and neurogenic bowel management is essential not just for medical safety, but also for optimal psychosocial integration into the child’s expanding social circle.

Dietary Intake and Genetic Background Influence Vitamin Needs during Pregnancy

Numerous approaches demonstrate how nutritional intake can be sufficient to ensure the necessary supply of vitamins. However, it is evident that not all vitamins are contained in all foods, so it is necessary either to combine different food groups or to use a vitamin supplement to be well-fed. During pregnancy, deficiencies are often exacerbated due to increased energy and nutritional demands, causing adverse outcomes in mother and child. Micronutrient supplementation could lead to optimal pregnancy outcomes being essential for proper metabolic activities that are involved in tissue growth and functioning in the developing fetus. In order to establish adequate vitamin supplementation, various conditions should be considered, such as metabolism, nutrition and genetic elements. This review accurately evaluated vitamin requirements and possible toxic effects during pregnancy. Much attention was given to investigate the mechanisms of cell response and risk assessment of practical applications to improve quality of life. Importantly, genetic studies suggest that common allelic variants and polymorphisms may play an important role in vitamin metabolism during pregnancy. Changes in gene expression of different proteins involved in micronutrients’ metabolism may influence the physiological needs of the pregnant woman.

Identification of new candidate genes for spina bifida through exome sequencing

PURPOSE

Neural tube defects are a group of birth defects caused by failure of neural tube closure during development. The etiology of NTD, requiring a complex interaction between environmental and genetic factors, is not well understood.

METHODS

We performed whole-exome sequencing (WES) in six trios, with a single affected proband with spina bifida, to identify rare/novel variants as potential causes of the NTD.

RESULTS

Our analysis identified four de novo and ten X-linked recessive variants in four of the six probands, all of them in genes previously never implicated in NTD. Among the 14 variants, we ruled out six of them, based on different criteria and pursued the evaluation of eight potential candidates in the following genes: RXRγ, DTX1, COL15A1, ARHGAP36, TKTL1, AMOT, GPR50, and NKRF. The de novo variants where located in the RXRγ, DTX1, and COL15A1 genes while ARHGAP36, TKTL1, AMOT, GPR50, and NKRF carry X-linked recessive variants. This analysis also revealed that four patients presented multiple variants, while we were unable to identify any significant variant in two patients.

CONCLUSIONS

Our preliminary conclusion support a major role for the de novo variants with respect to the X-linked recessive variants where the X-linked could represent a contribution to the phenotype in an oligogenic model.

Prevalence of open neural tube defects and risk factors related to isolated anencephaly and spina bifida in live births from the "Dr. Juan I. Menchaca" Civil Hospital of Guadalajara (Jalisco, Mexico)

We determine the prevalence and trends of open neural tube defects (ONTDs) during 1991 to 2019 at the "Dr. Juan I. Menchaca" Civil Hospital of Guadalajara (Mexico). Also, details of potential risks were obtained in 662 newborns, including those 143 patients with anencephaly and open spina bifida (OSB) classified as isolated (cases) and 519 controls. Data were analyzed using multivariable logistic regression. Among 267 201 live births during the study period, 336 were born with ONTDs, yielding an overall prevalence of 12.6 per 10 000. After folic acid (FA)-related programs began in Mexico (2003-2019), only OSB showed a decline of 20.6%. For anencephaly, associated risks included relatives with neural tube defects (NTDs) (adjusted odds ratio [aOR]: 67.9, 95% confidence interval [95% CI]: 11.3-409.8), pre-pregnancy body mass index (BMI) ≥25 kg/m² (aOR: 2.6, 95% CI: 1.1-6.0), insufficient gestational weight gain (aOR: 3.0, 95% CI: 1.3-7.1), parity ≥4 (aOR: 3.2, 95% CI: 1.3-7.7), and exposure to analgesic/antipyretic drugs (aOR: 9.0; 95% CI: 2.5-33.0). For OSB, associated risks included consanguinity (aOR: 14.0, 95% CI: 3.5-55.9), relatives with NTDs (aOR: 22.4, 95% CI: 4.5-112.9), BMI ≥25 kg/m² (aOR: 2.5, 95% CI: 1.6-4.2), insufficient gestational weight gain (aOR: 1.9, 95% CI: 1.1-3.1), and exposures to hyperthermia (aOR: 2.3, 95% CI: 1.2-4.3), common cold (aOR: 6.8, 95% CI: 3.6-12.7), and analgesic/antipyretic drugs (aOR: 3.6, 95% CI: 1.3-10.0). Our high rate probably results from exposures to preventable risks, most related to FA, indicating a need for strengthening existing FA-related programs in Mexico.

Developmental Toxicity of the Neural Tube Induced by Titanium Dioxide Nanoparticles in Mouse Embryos

Background:

This study investigated the potential effects of Titanium dioxide nanoparticles (Tio2NPs) followed by maternal gavage on fetal development and neural tube formation during pregnancy in mice.

Methods:

Thirty pregnant mice were randomly divided into five main study groups including the untreated control and 4 experimental groups (n=6 per group). The control group was treated with normal saline and the experimental groups were orally treated with doses of 30, 150, 300, and 500 mg/kg Body Weight (BW) of Tio2NPs during pregnancy. On gestational day 16 and 19 (n=3 per group), pregnant mice were euthanized and then examined for neural tube defects and compared with control. Serial transverse sections were prepared in both cranial region and in lumbar region of spinal cord.

Results:

Treatment with Tio2NPs resulted in low fetal weight and short length, dilation of lateral ventricle, thinning of cerebral cortex and spinal cord, spina bifida occulta and an increase in the number of apoptotic neurons in exposed embryos at doses of 300 and 500 mg/kg (p<0.05).

Conclusion:

It seems that exposure to nanoparticles of Tio2 during pregnancy induces growth retardation and for the first time, teratogenicity of this nanomaterial in neural tube development and induction of defects such as spinal bifida, reduction in cortical thickness and dilatation of lateral ventricles were verified which can be related to incidence of apoptosis in central nervous system.

Neural Tube Defects and Associated Factors among Neonates Admitted to the Neonatal Intensive Care Units in Hiwot Fana Specialized University Hospital, Harar, Ethiopia

Background:

Neural tube defects are a major public health problem and substantially contribute to morbidity and mortality, particularly in low-income countries, including Ethiopia. There are a paucity of data on the magnitude and associated factors of neural tube defects in Ethiopia, particularly in the study setting.

Objective:

This study aimed to assess the magnitude of neural tube defects and associated factors among neonates admitted to the neonatal intensive care unit in Hiwot Fana Specialized University Hospital, Harar, Ethiopia.

Methods:

A hospital-based cross-sectional study was employed from October 2019 to January 2020. A total of 420 newborn-mother pairs were included consecutively. Data were collected using a face-to-face interviewer-administered questionnaire and clinical examination. Data were entered into Epi Data version 3.1 and analyzed using the statistical package for Social Sciences version 20.0 software. An adjusted odds ratio (AOR) with 95% confidence interval (CI) was used to identify the associated factors. A p-value <.05 was considered statistically significant.

Results:

The magnitude of neural tube defects was 5.71% (95% CI: 3.5-7.9). Approximately 83.5% of infants had spinal bifida and 16.5% anencephaly. In multivariable logistic regression analyses, preterm birth (32-34 weeks) (AOR= 3.84; 95% CI: 2.1,10.7), low birth weight (1000-1500 g) (AOR = 4.74; 95% CI: 1.8, 9.1), 1500-2500 g (AOR = 3.01; 95% CI: 2. 1, 13.2), maternal coffee consumption (AOR = 11.2; 95% CI: 3.1, 23.7), a history of abortion or stillbirth (AOR = 9.6; 95% CI:7.6,19.4), radiation exposure (AOR = 5.0; 95% CI:1.6,14.3), and intake of anticonvulsant drugs during pregnancy (AOR = 4.75; 95% CI: 1.5,16.2) were factors associated with neural tube defects.

Conclusion:

In this study, the burden of neural tube defects was 5.71% among neonates admitted to the neonatal intensive care unit, which was a public health concern. Increased attention to the monitoring of neural tube defects in eastern Ethiopia is crucial to improve birth outcomes in the study setting.

Maternal intake of one-carbon metabolism-related B vitamins and anorectal malformations in the Japan Environment and Children's Study

The occurrence of anorectal malformations (ARM) is thought to be reduced with sufficient folate intake. However, there is no apparent evidence. We focused on enzyme cofactors for one-carbon metabolism, including folate (vitamin B9), vitamin B6 and vitamin B12, and explored the association between maternal combined intake of these B vitamins and the risk of ARM. Using baseline data from a Japanese nationwide birth cohort study between 2011 and 2014, we analysed data of 89 235 women (mean age at delivery = 31·2 years) who delivered singleton live births without chromosomal anomalies. Information on dietary intake was obtained via a FFQ focused on early pregnancy and used to estimate B vitamin intake. We also collected information on the frequency of folic acid supplement use. ARM occurrence was ascertained from medical records. We identified forty-three cases of ARM diagnosed up to the first month after birth (4·8 per 10 000 live births). In terms of individual intake of the respective B vitamins, high vitamin B6 intake was non-significantly associated with reduced odds of ARM. Compared with women in the low combined B vitamin intake group, the OR of having an infant with ARM was 0·4 (95 % CI 0·2, 1·0) in the high intake group (folate ≥400 μg/d, and upper half of vitamin B6 and/or vitamin B12). In conclusion, our cohort analysis suggested an inverse association between the combined intake of one-carbon metabolism-related B vitamins in early pregnancy and ARM occurrence.

Folic acid prescribed to prenatal and postpartum women who are also prescribed antiepileptic drugs in Japan: Data from a health administrative database

BACKGROUND

The aim of this study was to evaluate the prevalence of folic acid (FA) prescription to prenatal and postpartum women who have also been prescribed antiepileptic drugs (AED) in Japan.

METHODS

The data set used in this study included women covered by health insurance between 2005 and 2016. The prevalence of FA prescriptions between 180 days before pregnancy and 180 days postpartum was determined from a large administrative database, with the FA prescription classified according to dose and timing.

RESULTS

For 33,941 women meeting our eligibility criteria, the mean maternal age at delivery was 32.3 years. At least one AED was prescribed to 225 of 33,941 women between 180 days before pregnancy and 180 days postpartum. FA was prescribed to 32 of 225 women (14.2%) during the same period. FA was prescribed to 8.8% of women with AED within 90 days before pregnancy and to 19.8% during the first trimester. FA was prescribed to 10.9% during the first 30 days after conception, all of whom were prescribed FA before the pregnancy. The maximum FA dose prescribed within 90 days before pregnancy was 5 mg/day for 5 of 12 women (41.7%) and >5 mg/day for 4 of 12 women (33.3%). The maximum FA dose prescribed during the first trimester was 5 mg/day for 14 of 22 women (63.6%) and >5 mg/day for 8 of 22 women (36.4%).

CONCLUSIONS

The concurrent prescription of FA with AEDs in Japan was an uncommon therapeutic approach both before and during pregnancy.

F-box protein FBXO30 mediates retinoic acid receptor γ ubiquitination and regulates BMP signaling in neural tube defects

Retinoic acid (RA), an active derivative of vitamin A, is critical for the neural system development. During the neural development, the RA/RA receptor (RAR) pathway suppresses BMP signaling-mediated proliferation and differentiation of neural progenitor cells. However, how the stability of RAR is regulated during neural system development and how BMP pathway genes expression in neural tissue from human fetuses affected with neural tube defects (NTDs) remain elusive. Here, we report that FBXO30 acts as an E3 ubiquitin ligase and targets RARγ for ubiquitination and proteasomal degradation. In this way, FBXO30 positively regulates BMP signaling in mammalian cells. Moreover, RA treatment leads to suppression of BMP signaling by reducing the level of FBXO30 in mammalian cells and in mouse embryos with NTDs. In samples from human NTDs with high levels of retinol, downregulation of BMP target genes was observed, along with aberrant FBXO30 levels. Collectively, our results demonstrate that RARγ levels are controlled by FBXO30-mediated ubiquitination and that FBXO30 is a key regulator of BMP signaling. Furthermore, we suggest a novel mechanism by which high-retinol levels affect the level of FBXO30, which antagonizes BMP signaling during early stage development.

Real prevalence of neural tube defects in Japan: How many of such pregnancies have been terminated?

The vital role of folic acid is to reduce the risk of having a neonate afflicted with neural tube defects. The prevalence of neural tube defects (myelomeningocele and anencephaly) has been reported in an incomplete form over the last 40 years in Japan. We aimed to evaluate the total number of neural tube defects including those delivered or terminated, to clarify the proportion of those terminated, and to internationally compare their prevalence. Through information on >311 000 deliveries obtained from 262 hospitals/clinics for 2 years of 2014 and 2015, we identified that the rate of total neural tube defects (termination of pregnancy, live births and stillbirths) was 8.29 per 10 000 deliveries for the year 2014 and was 8.72 for 2015, which were 1.5 and 1.6 times higher than the respective values (live births and stillbirths) reported. It is also observed that the ratio of the total number of myelomeningocele (termination of pregnancy, live births, and stillbirths) to that of anencephaly was approximately 1:1.2, that a half of pregnancies afflicted with neural tube defects were terminated, and that the proportion of termination of pregnancy due to myelomeningocele and due to anencephaly was 20% and 80%, respectively. Internationally, the real prevalence of neural tube defects in Japan was comparatively high, ranking fifth among the seven developed countries. In conclusion, the real prevalence of total neural tube defects was approximately 1.5 times higher than that currently reported by the Japan Association of Obstetricians and Gynecologists.

Preconception folic acid supplementation use and the occurrence of neural tube defects in Japan: A nationwide birth cohort study of the Japan Environment and Children's Study

We evaluated the relationship between preconception folic acid supplementation and the occurrence of neural tube defects (NTDs) in offspring, using data from the Japan Environment and Children's Study (a nationwide prospective birth cohort study) database. Of 92 269 participants with single pregnancies, 74 cases (offspring or fetuses) had NTDs, including 32 cases of spina bifida, 24 cases of anencephaly, and 19 cases of encephalocele. A total of 7634 participants (8.27%) used preconception folic acid supplementation, and of these, 621 (0.67%) also took in dietary folic acid at ≥480 μg/day. Multivariate logistic regression analyses demonstrated no association between preconception folic acid supplementation and NTDs in offspring or fetuses (odds ratio [OR] 0.622; 95% confidence interval [CI]: 0.226-1.713). Moreover, the participants who combined preconception folic acid supplement use with dietary folic acid intake ≥480 μg/day demonstrated no incidence of NTDs in offspring or fetuses. Our analysis is limited by the absence of the data on the daily amount of supplementary folic acid intake, requiring careful attention to the interpretation. Additional surveys are required in Japan to resolve those limitations for further comprehensive assessment.