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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 -
Congenital Anomalies Sep 2017Folate functions as a coenzyme to transfer one-carbon units that are necessary for deoxythymidylate synthesis, purine synthesis, and various methylation reactions.... (Review)
Review
Folate functions as a coenzyme to transfer one-carbon units that are necessary for deoxythymidylate synthesis, purine synthesis, and various methylation reactions. Ingested folate becomes a functional molecule through intestinal absorption, circulation, transport to cells, and various modifications to its structure. Associations between nutritional folate status and chronic diseases such as cardiovascular disease, cancer, and cognitive dysfunction have been reported. It has also been reported that maternal folate nutritional status is related to the risk of neural tube defects (NTDs) in the offspring. It has also been recommended that folate be consumed in the diet to promote the maintenance of good health. To reduce the risk of NTDs, supplementation with folic acid (a synthetic form of folate) during the periconceptional period has also been recommended. This paper describes the basic features and nutritional role of folate.
Topics: Dietary Supplements; Embryo, Mammalian; Female; Fetus; Folic Acid; Folic Acid Deficiency; Humans; Metabolic Networks and Pathways; Neural Tube; Neural Tube Defects; Recommended Dietary Allowances
PubMed: 28603928
DOI: 10.1111/cga.12233 -
Child's Nervous System : ChNS :... Jul 2023Neural tube defects (NTDs) are common birth defects and contribute to life-long disabilities, high medical care costs, and perinatal and child mortality. This review is... (Review)
Review
Neural tube defects (NTDs) are common birth defects and contribute to life-long disabilities, high medical care costs, and perinatal and child mortality. This review is a primer on prevalence, causes, and evidence-based prevention strategies for NTDs. The estimated average global prevalence of NTDs is two cases per 1000 births, amounting to approximately 214,000-322,000 affected pregnancies worldwide annually. Prevalence and associated adverse outcomes are disproportionately high in developing countries. NTDs have multiple risk factors including genetic and non-genetic (i.e., maternal nutritional status, pre-pregnancy diabetes, early pregnancy exposure to valproic acid (anti-epileptic medication), and a previous pregnancy affected by a NTD) factors. Maternal folate insufficiency before and during early pregnancy is the most common risk factor and is preventable. Folic acid (vitamin B9) is required for formation of the neural tube early in pregnancy, around 28 days after conception, when most women are unaware of their pregnancies. Current guidelines recommend that all women planning or capable of pregnancy take a daily supplement containing 400-800 μg of folic acid. Mandatory folic acid fortification of staple foods (e.g., wheat flour, maize flour, rice) is safe, economical, and the effective intervention for primary prevention of NTDs. Currently, about 60 countries are implementing mandatory folic acid fortification of staple foods, preventing just a quarter of all preventable NTD cases worldwide. There is an urgent need for active champions, including neurosurgeons and other healthcare providers, to generate political will and promote effective mandatory food fortification with folic acid, and reach equitable primary prevention of NTDs in all countries.
Topics: Pregnancy; Child; Female; Humans; Flour; Prevalence; Food, Fortified; Triticum; Neural Tube Defects; Folic Acid; Primary Prevention
PubMed: 36882610
DOI: 10.1007/s00381-023-05910-7 -
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 Obstetrics and Gynaecology... Jan 2021This revised guideline is intended to provide an update on the genetic aspects, prevention, screening, diagnosis, and management of fetal neural tube defects.
OBJECTIVE
This revised guideline is intended to provide an update on the genetic aspects, prevention, screening, diagnosis, and management of fetal neural tube defects.
TARGET POPULATION
Women who are pregnant or may become pregnant. Neural tube defect screening should be offered to all pregnant women.
OPTIONS
For prevention: a folate-rich diet, and folic acid and vitamin B supplementation, with dosage depending on risk level. For screening: second-trimester anatomical sonography; first-trimester sonographic screening; maternal serum alpha fetoprotein; prenatal magnetic resonance imaging. For genetic testing: diagnostic amniocentesis with chromosomal microarray and amniotic fluid alpha fetoprotein and acetylcholinesterase; fetal exome sequencing. For pregnancy management: prenatal surgical repair; postnatal surgical repair; pregnancy termination with autopsy. For subsequent pregnancies: prevention and screening options and counselling.
OUTCOMES
The research on and implementation of fetal surgery for prenatally diagnosed myelomeningocele has added a significant treatment option to the previous options (postnatal repair or pregnancy termination), but this new option carries an increased risk of maternal morbidity. Significant improvements in health and quality of life, both for the mother and the infant, have been shown to result from the prevention, screening, diagnosis, and treatment of fetal neural tube defects.
BENEFITS, HARMS, AND COSTS
The benefits for patient autonomy and decision-making are provided in the guideline. Harms include an unexpected fetal diagnosis and the subsequent management decisions. Harm can also result if the patient declines routine sonographic scans or if counselling and access to care for neural tube defects are delayed. Cost analysis (personal, family, health care) is not within the scope of this clinical practice guideline.
EVIDENCE
A directed and focused literature review was conducted using the search terms spina bifida, neural tube defect, myelomeningocele, prenatal diagnosis, fetal surgery, neural tube defect prevention, neural tube defect screening, neural tube defect diagnosis, and neural tube defect management in order to update and revise this guideline. A peer review process was used for content validation and clarity, with appropriate ethical considerations.
VALIDATION METHODS
The authors rated the quality of evidence and strength of recommendations using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach. See online Appendix A (Tables A1 for definitions and A2 for interpretations of strong and weak recommendations).
INTENDED AUDIENCE
Maternity care professionals who provide any part of pre-conception, antenatal, delivery, and neonatal care. This guideline is also appropriate for patient education. RECOMMENDATIONS (GRADE RATINGS IN PARENTHESES).
Topics: Female; Genetic Testing; Humans; Maternal Health Services; Neural Tube Defects; Pregnancy; Prenatal Care; Prenatal Diagnosis; Quality of Life; Societies, Medical
PubMed: 33212246
DOI: 10.1016/j.jogc.2020.11.003 -
Cellular and Molecular Life Sciences :... Nov 2022Gastrulation and neurulation are successive morphogenetic processes that play key roles in shaping the basic embryonic body plan. Importantly, they operate through... (Review)
Review
Gastrulation and neurulation are successive morphogenetic processes that play key roles in shaping the basic embryonic body plan. Importantly, they operate through common cellular and molecular mechanisms to set up the three spatially organized germ layers and to close the neural tube. During gastrulation and neurulation, convergent extension movements driven by cell intercalation and oriented cell division generate major forces to narrow the germ layers along the mediolateral axis and elongate the embryo in the anteroposterior direction. Apical constriction also makes an important contribution to promote the formation of the blastopore and the bending of the neural plate. Planar cell polarity proteins are major regulators of asymmetric cell behaviors and critically involved in a wide variety of developmental processes, from gastrulation and neurulation to organogenesis. Mutations of planar cell polarity genes can lead to general defects in the morphogenesis of different organs and the co-existence of distinct congenital diseases, such as spina bifida, hearing deficits, kidney diseases, and limb elongation defects. This review outlines our current understanding of non-canonical Wnt signaling, commonly known as Wnt/planar cell polarity signaling, in regulating morphogenetic movements of gastrulation and neural tube closure during development and disease. It also attempts to identify unanswered questions that deserve further investigations.
Topics: Humans; Neurulation; Gastrulation; Cell Polarity; Wnt Signaling Pathway; Neural Tube; Morphogenesis; Neural Tube Defects
PubMed: 36369349
DOI: 10.1007/s00018-022-04620-8 -
Journal of Neurosurgery. Pediatrics Aug 2014Acalvaria is a rare congenital malformation characterized by an absence of skin and skull. The authors describe a newborn at an estimated 38 weeks gestational age who...
Acalvaria is a rare congenital malformation characterized by an absence of skin and skull. The authors describe a newborn at an estimated 38 weeks gestational age who was delivered via cesarean section from a 32-year-old mother. Upon delivery, the child was noted to have a frontal encephalocele and an absence of calvaria including skull and skin overlying the brain. A thin membrane representing dura mater was overlying the cortical tissue. After multiple craniofacial operations, including repair of the encephalocele and application of cultured keratinocytes over the rostral defect, the patient demonstrated significant closure of the calvarial defect and was alive at an age of more than 17 months with near-average development.
Topics: Brain; Dura Mater; Encephalocele; Female; Gestational Age; Humans; Imaging, Three-Dimensional; Infant; Infant, Newborn; Neural Tube Defects; Pregnancy; Prenatal Diagnosis; Scalp; Skull; Tomography, X-Ray Computed; Treatment Outcome
PubMed: 24926969
DOI: 10.3171/2014.5.PEDS13688 -
American Journal of Obstetrics and... Dec 2020
Review
Topics: Abortion, Induced; Amniotic Band Syndrome; Anencephaly; Bone Diseases, Developmental; Diagnosis, Differential; Digestive System Abnormalities; Female; Heart Defects, Congenital; Hernias, Diaphragmatic, Congenital; Humans; Karyotyping; Kidney; Microarray Analysis; Microcephaly; Neural Tube Defects; Palliative Care; Pregnancy; Severity of Illness Index; Spina Bifida Cystica; Triploidy; Trisomy; Ultrasonography, Prenatal
PubMed: 33168213
DOI: 10.1016/j.ajog.2020.08.176 -
Pediatrics in Review Dec 2019
Review
Topics: Child; Cutaneous Fistula; Humans; Infant; Neural Tube Defects; Spine
PubMed: 31792051
DOI: 10.1542/pir.2018-0155 -
The Pan African Medical Journal 2017Diastematomyelia is a rare spinal dysraphism in which the spinal cord and its content are split. Two types of diastematomyelia have been described. We report the case of...
Diastematomyelia is a rare spinal dysraphism in which the spinal cord and its content are split. Two types of diastematomyelia have been described. We report the case of a 12 year old male patient presenting with reduced lower limb muscle strength without associated sphincteric disorders. The patient underwent axial, sagittal and coronal T1 and T2-weighted MRI sequence of the spine. MRI showed a bifid appearance of the bone marrow of thoracolumbar vertebrae in two hemi-cords without bone spur separating the two hemi-marrows, compatible with type 1 diastematomyelia. It was associated with low tethered spinal cord with syringomyelic cavity involving the left hemi-marrow and with biloculated fibrotic lesion at the level of the right hemi-marrow compatible with a neuroenteric cyst. MRI also showed incomplete closure of the posterior arch of D12 vertebra which communicated with a subcutaneous pocket in relation to a dermal sinus. Diastematomyelia is a rare abnormality of the spine which can be associated with other malformations. Therapeutic strategy essentially depends on the progression of the clinical signs (neurological) and of associated malformations.
Topics: Child; Humans; Magnetic Resonance Imaging; Male; Neural Tube Defects; Spinal Cord; Spinal Dysraphism
PubMed: 29721147
DOI: 10.11604/pamj.2017.28.317.14500