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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 -
Cell May 2023Neural tube (NT) defects arise from abnormal neurulation and result in the most common birth defects worldwide. Yet, mechanisms of primate neurulation remain largely...
Neural tube (NT) defects arise from abnormal neurulation and result in the most common birth defects worldwide. Yet, mechanisms of primate neurulation remain largely unknown due to prohibitions on human embryo research and limitations of available model systems. Here, we establish a three-dimensional (3D) prolonged in vitro culture (pIVC) system supporting cynomolgus monkey embryo development from 7 to 25 days post-fertilization. Through single-cell multi-omics analyses, we demonstrate that pIVC embryos form three germ layers, including primordial germ cells, and establish proper DNA methylation and chromatin accessibility through advanced gastrulation stages. In addition, pIVC embryo immunofluorescence confirms neural crest formation, NT closure, and neural progenitor regionalization. Finally, we demonstrate that the transcriptional profiles and morphogenetics of pIVC embryos resemble key features of similarly staged in vivo cynomolgus and human embryos. This work therefore describes a system to study non-human primate embryogenesis through advanced gastrulation and early neurulation.
Topics: Animals; Humans; Blastocyst; Embryo, Mammalian; Embryonic Development; Macaca fascicularis; Neural Tube Defects; Neurulation; Tissue Culture Techniques
PubMed: 37172562
DOI: 10.1016/j.cell.2023.04.019 -
The Lancet. Neurology Aug 2013Neural tube defects are severe congenital malformations affecting around one in every 1000 pregnancies. An innovation in clinical management has come from the finding... (Review)
Review
Neural tube defects are severe congenital malformations affecting around one in every 1000 pregnancies. An innovation in clinical management has come from the finding that closure of open spina bifida lesions in utero can diminish neurological dysfunction in children. Primary prevention with folic acid has been enhanced through introduction of mandatory food fortification in some countries, although not yet in the UK. Genetic predisposition accounts for most of the risk of neural tube defects, and genes that regulate folate one-carbon metabolism and planar cell polarity have been strongly implicated. The sequence of human neural tube closure events remains controversial, but studies of mouse models of neural tube defects show that anencephaly, open spina bifida, and craniorachischisis result from failure of primary neurulation, whereas skin-covered spinal dysraphism results from defective secondary neurulation. Other malformations, such as encephalocele, are likely to be postneurulation disorders.
Topics: Animals; Databases, Factual; Disease Models, Animal; Folic Acid; Genetic Predisposition to Disease; Humans; Methylenetetrahydrofolate Reductase (NADPH2); Mutation; Neural Tube Defects
PubMed: 23790957
DOI: 10.1016/S1474-4422(13)70110-8 -
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 -
The Pan African Medical Journal 2023
Topics: Humans; Neural Tube Defects
PubMed: 37013212
DOI: 10.11604/pamj.2023.44.24.35962 -
Taiwanese Journal of Obstetrics &... Sep 2007Iniencephaly is characterized by a variable deficit of the occipital bones, resulting in an enlarged foramen magnum; partial or total absence of cervical and thoracic... (Review)
Review
Iniencephaly is characterized by a variable deficit of the occipital bones, resulting in an enlarged foramen magnum; partial or total absence of cervical and thoracic vertebrae with an irregular fusion of those present, accompanied by incomplete closure of the vertebral arches and/or bodies; significant shortening of the spinal column due to marked lordosis and hyperextension of the malformed cervicothoracic spine; and an upward-turned face and mandibular skin directly continuous with that of the chest due to the lack of neck. This article provides a comprehensive review of the reported cases of prenatally detected iniencephaly, including prenatal diagnosis, associated malformations, associated chromosomal abnormalities, and differential diagnosis. Prenatal diagnosis of a neural tube defect involving a body defect in the occiput and rachischisis of the cervical and thoracic spine with retroflexion of the head should raise the suspicion of iniencephaly. Iniencephaly may be associated with craniorachischisis and other structural anomalies. Prenatal diagnosis of non-isolated iniencephaly and craniorachischisis should alert one to the possibility of chromosomal abnormalities and prompt a cytogenetic investigation.
Topics: Diagnosis, Differential; Female; Fetal Diseases; Humans; Neural Tube Defects; Pregnancy; Prenatal Diagnosis
PubMed: 17962097
DOI: 10.1016/S1028-4559(08)60021-2 -
Revista Medica Del Instituto Mexicano... Feb 2022Neural tube defects are a heterogeneous group of alterations of the central nervous system with multifactorial origin, mainly caused by a failure in the mechanisms of...
BACKGROUND
Neural tube defects are a heterogeneous group of alterations of the central nervous system with multifactorial origin, mainly caused by a failure in the mechanisms of closure of the neural tube which involves skin, paravertebral muscles, connective tissue, bone and spinal cord.
CLINICAL CASE
36-year-old woman with a pregnancy of 25.3 weeks, corroborated by second trimester ultrasound. She had a previous pregnancy with anencephaly and a poor prenatal care in the actual pregnancy. An obstetric ultrasound was performed with the diagnosis of craniorachischisis, which is why the delivery was performed by vaginal birth with labor induction with prostaglandins.
CONCLUSIONS
The craniorachischisis is a rare defect of the neural tube that must be diagnosed early because it is a pathology incompatible with life.
Topics: Adult; Anencephaly; Central Nervous System; Female; Humans; Neural Tube Defects; Pregnancy; Ultrasonography, Prenatal
PubMed: 35274915
DOI: No ID Found -
BMJ Case Reports Apr 2022Craniorachischisis totalis (anencephaly with total open spina bifida) is the most severe form of neural tube defects. The exact aetiology of neural tube defects remains...
Craniorachischisis totalis (anencephaly with total open spina bifida) is the most severe form of neural tube defects. The exact aetiology of neural tube defects remains poorly understood. We report a case of a primigravida in her 20s with a fetus in which craniorachischisis totalis was diagnosed during the first-trimester ultrasound at 11 weeks of gestation. The parents opted for pregnancy termination and the diagnosis was confirmed postnatally. Besides the lack of folic acid supplementation during preconception, no other risk factor was found. This case highlights the importance of the first-trimester ultrasound in the diagnosis of severe malformations. The right diagnosis is crucial for future prenatal counselling, yet investigation is still required to better understand the aetiology behind neural tube defects and assess the possibility of underlying genetic features, thus enabling better counselling.
Topics: Abortion, Induced; Anencephaly; Female; Fetus; Humans; Neural Tube Defects; Pregnancy; Prenatal Diagnosis
PubMed: 35470163
DOI: 10.1136/bcr-2021-244682 -
Taiwanese Journal of Obstetrics &... Sep 2009To present the prenatal magnetic resonance imaging (MRI) findings of concomitant craniorachischisis and omphalocele, review the literature, and discuss the pathogenesis. (Review)
Review
OBJECTIVE
To present the prenatal magnetic resonance imaging (MRI) findings of concomitant craniorachischisis and omphalocele, review the literature, and discuss the pathogenesis.
CASE REPORT
A 20-year-old, gravida 2, para 0, woman was referred to genetic counseling at 17 weeks of gestation because of multiple congenital malformations in the fetus. Level II ultrasound revealed acrania, a ventricular septal defect, an upward-turned face, and omphalocele containing the intestines. MRI revealed normal extremities, exencephaly, hyperextension of the fetal head, significant shortening of the spinal column, marked lordosis and hyperextension of the malformed spine, an upward-turned face, and absence of a neck. A diagnosis of iniencephaly associated with anencephaly, rachischisis and omphalocele was made. Amniocentesis revealed a karyotype of 46,XY. Postnatal X-ray showed anencephaly with total spina bifida of the cervical and thoracic spine.
CONCLUSION
Prenatal MRI is able to provide a clear whole-body image of the fetus and its relationship with the placenta. Prenatal MRI is very useful in the differential diagnosis of concomitant craniorachischisis and omphalocele from amniotic band sequence, limb body-wall complex with craniofacial defect and Disorganization human homologue.
Topics: Female; Hernia, Umbilical; Humans; Magnetic Resonance Imaging; Male; Neural Tube Defects; Pregnancy; Prenatal Diagnosis; Young Adult
PubMed: 19797022
DOI: 10.1016/S1028-4559(09)60306-5