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Annual Review of Neuroscience 2014Neural tube defects (NTDs), including spina bifida and anencephaly, are severe birth defects of the central nervous system that originate during embryonic development... (Review)
Review
Neural tube defects (NTDs), including spina bifida and anencephaly, are severe birth defects of the central nervous system that originate during embryonic development when the neural tube fails to close completely. Human NTDs are multifactorial, with contributions from both genetic and environmental factors. The genetic basis is not yet well understood, but several nongenetic risk factors have been identified as have possibilities for prevention by maternal folic acid supplementation. Mechanisms underlying neural tube closure and NTDs may be informed by experimental models, which have revealed numerous genes whose abnormal function causes NTDs and have provided details of critical cellular and morphological events whose regulation is essential for closure. Such models also provide an opportunity to investigate potential risk factors and to develop novel preventive therapies.
Topics: Animals; Folic Acid; Genetic Predisposition to Disease; Humans; Neural Tube Defects; Neurulation; Risk Factors
PubMed: 25032496
DOI: 10.1146/annurev-neuro-062012-170354 -
Birth Defects Research Nov 2019Neural tube defects (NTDs) are the second most common congenital malformations in humans affecting the development of the central nervous system. Although NTD... (Review)
Review
Neural tube defects (NTDs) are the second most common congenital malformations in humans affecting the development of the central nervous system. Although NTD pathogenesis has not yet been fully elucidated, many risk factors, both genetic and environmental, have been extensively reported. Classically divided in two main sub-groups (open and closed defects) NTDs present extremely variable prognosis mainly depending on the site of the lesion. Herein, we review the literature on the histological and pathological features, epidemiology, prenatal diagnosis, and prognosis, based on the type of defect, with the aim of providing important information based on NTDs classification for clinicians and scientists.
Topics: Anencephaly; Female; Humans; Neural Tube Defects; Pregnancy; Prenatal Diagnosis; Risk Factors
PubMed: 30421543
DOI: 10.1002/bdr2.1380 -
Trends in Neurosciences Jul 2020Neural tube defects (NTDs) represent a failure of the neural plate to complete the developmental transition to a neural tube. NTDs are the most common birth anomaly of... (Review)
Review
Neural tube defects (NTDs) represent a failure of the neural plate to complete the developmental transition to a neural tube. NTDs are the most common birth anomaly of the CNS. Following mandatory folic acid fortification of dietary grains, a dramatic reduction in the incidence of NTDs was observed in areas where the policy was implemented, yet the genetic drivers of NTDs in humans, and the mechanisms by which folic acid prevents disease, remain disputed. Here, we discuss current understanding of human NTD genetics, recent advances regarding potential mechanisms by which folic acid might modify risk through effects on the epigenome and transcriptome, and new approaches to study refined phenotypes for a greater appreciation of the developmental and genetic causes of NTDs.
Topics: Folic Acid; Humans; Neural Tube Defects
PubMed: 32423763
DOI: 10.1016/j.tins.2020.04.009 -
Journal of Clinical Pharmacology Feb 2016During the last decade critical new information has been published pertaining to folic acid supplementation in the prevention of neural tube defects (NTDs) and other... (Review)
Review
During the last decade critical new information has been published pertaining to folic acid supplementation in the prevention of neural tube defects (NTDs) and other folic acid-sensitive congenital malformations. These new data have important implications for women, their families, and health care professionals. We performed a review looking for the optimal dosage of folic acid that should be given to women of reproductive age who are planning or not avoiding conception to propose updated guidelines and thus help health care providers and patients. In addition to fortification of dietary staples with folic acid, women of reproductive age should supplement before conception with 0.4-1.0 mg of folic acid daily as part of their multivitamins. In the United States all enriched rice is also fortified with folic acid at 0.7 mg per pound of raw rice. However, this is not the case in many countries, and it has been estimated that only 1% of industrially milled rice is fortified with folic acid. In countries where rice is the main staple (eg, China), this does not allow effective folate fortification. Whereas the incidence of NTDs is around 1/1000 in the United States, it is 3- to 5-fold higher in Northern China and 3-fold higher in India. A recent population-based US study estimated that the reduction in NTD rates by folic acid is more modest than previously predicted. The potential of NTD prevention by folic acid is underutilized due to low adherence with folic acid supplementation, and calls for revising the policy of supplementation have been raised. We identified groups of women of reproductive age who may benefit from higher daily doses of folic acid, and this should be considered in current practice. These include women who have had previous pregnancies with NTDs, those who did not plan their pregnancy and hence did not supplement, and women with low intake or impaired adherence to daily folic acid supplementation. In addition, women with known genetic variations in the folate metabolic cycle, those exposed to medications with antifolate effects, smokers, diabetics, and the obese may benefit from higher doses of folic acid daily during the first trimester.
Topics: Anencephaly; Dietary Supplements; Dose-Response Relationship, Drug; Female; Folic Acid; Humans; Pregnancy; Vitamins
PubMed: 26272218
DOI: 10.1002/jcph.616 -
The Pan African Medical Journal 2023
Topics: Humans; Neural Tube Defects
PubMed: 37013212
DOI: 10.11604/pamj.2023.44.24.35962 -
Romanian Journal of Morphology and... 2020Anencephaly is a severe malformation of the central nervous system (CNS), being one of the most common types of neural tube defects. It is defined as total or partial... (Review)
Review
Anencephaly is a severe malformation of the central nervous system (CNS), being one of the most common types of neural tube defects. It is defined as total or partial absence of the calvarium, with absence of the brain. Anencephaly has an incidence of 1 to 5 in every 1000 births, and the mortality rate is 100% during intrauterine life or within hours or days after birth. The etiology of anencephaly remains unclear, but various maternal-related environmental and genetic risk factors have been reported, which include diabetes, obesity, exposure to different drugs or toxins, genetic polymorphisms and mutations, as well as positive family history for neural tube defects. One of the most important nutritional factors in the development of anencephaly is folate deficiency. Methylenetetrahydrofolate reductase (MTHFR) gene codes the enzyme involved in the intracellular metabolism of folic acid; the 677C-T polymorphism of this gene causes the thermolability of the enzyme and decreased enzymatic activity, which is also dependent of folate plasmatic level. Etiopathogenesis of anencephaly includes several mutations in various other genes, such as: platelet-derived growth factor receptor alpha (PDGFRA), cadherin epidermal growth factor (EGF) laminin G (LAG) seven-pass G-type receptor 1 (CELSR1), Vang-like 1 (VANGL1) and Vang-like 2 (VANGL2), the last two being involved in the process of neurulation. Screening tests include maternal serum alpha-fetoprotein level and ultrasound (US) examination. During the first trimester US screening, anencephaly is now detected in all cases, but in order to decrease the complication rate of pregnancy termination, the diagnosis should be established as soon as possible, during the pregnancy confirmation US. We conclude that given that anencephaly is a severe malformation of the CNS, morphological characterization could improve the screening by US that is mandatory in the first trimester in order to plan the best, safe and early management.
Topics: Anencephaly; Female; Humans; Male; Polymorphism, Genetic
PubMed: 33544785
DOI: 10.47162/RJME.61.2.03 -
Radiology Case Reports Feb 2021Meroanencephaly occurs when there is an incomplete open median calvarial defect. This condition, which is in the spectrum of anencephaly, results in ectopic brain...
Meroanencephaly occurs when there is an incomplete open median calvarial defect. This condition, which is in the spectrum of anencephaly, results in ectopic brain without skin covering and a normal foramen magnum. We present a rare case of a female fetus with meroanencephaly referred to our institution at 24 weeks and imaged with both prenatal ultrasound and MRI, demonstrating an open neural tube defect in the high parietal area and lack of visualization of the supratentorial ventricular system. Postnatal the child survived and went on to require antibiotic therapy and closure of the defect without cerebral spinal fluid diversion but demonstrates severe permanent neurologic deficits.
PubMed: 33343779
DOI: 10.1016/j.radcr.2020.12.006 -
Birth Defects Research Jan 2020Neural tube defects (NTDs) result from failure of neural tube closure during embryogenesis. These severe birth defects of the central nervous system include anencephaly...
BACKGROUND
Neural tube defects (NTDs) result from failure of neural tube closure during embryogenesis. These severe birth defects of the central nervous system include anencephaly and spina bifida, and affect 0.5-2 per 1,000 pregnancies worldwide in humans. It has been demonstrated that acetylation plays a pivotal role during neural tube closure, as animal models for defective histone acetyltransferase proteins display NTDs. Acetylation represents an important component of the complex network of posttranslational regulatory interactions, suggesting a possible fundamental role during primary neurulation events. This study aimed to assess protein acetylation contribution to early patterning of the central nervous system both in human and murine specimens.
METHODS
We used both human and mouse (Cited2 ) samples to analyze the dynamic acetylation of proteins during embryo development through immunohistochemistry, western blot analysis and quantitative polymerase chain reaction.
RESULTS
We report the dynamic profile of histone and protein acetylation status during neural tube closure. We also report a rescue effect in an animal model by chemical p53 inhibition.
CONCLUSIONS
Our data suggest that the p53-acetylation equilibrium may play a role in primary neurulation in mammals.
Topics: Acetylation; Anencephaly; Animals; Disease Models, Animal; Embryonic Development; Histone Acetyltransferases; Humans; Mammals; Mice; Neural Tube Defects; Neurulation; Repressor Proteins; Spinal Dysraphism; Trans-Activators; Transcription Factors; Tumor Suppressor Protein p53
PubMed: 31758757
DOI: 10.1002/bdr2.1618