title: Spina bifida.
abstract: Spina bifida is a birth defect in which the vertebral column is open, often with spinal cord involvement. The most clinically significant subtype is myelomeningocele (open spina bifida), which is a condition characterized by failure of the lumbosacral spinal neural tube to close during embryonic development. The exposed neural tissue degenerates in utero, resulting in neurological deficit that varies with the level of the lesion. Occurring in approximately 1 per 1,000 births worldwide, myelomeningocele is one of the most common congenital malformations, but its cause is largely unknown. The genetic component is estimated at 60-70%, but few causative genes have been identified to date, despite much information from mouse models. Non-genetic maternal risk factors include reduced folate intake, anticonvulsant therapy, diabetes mellitus and obesity. Primary prevention by periconceptional supplementation with folic acid has been demonstrated in clinical trials, leading to food fortification programmes in many countries. Prenatal diagnosis is achieved by ultrasonography, enabling women to seek termination of pregnancy. Individuals who survive to birth have their lesions closed surgically, with subsequent management of associated defects, including the Chiari II brain malformation, hydrocephalus, and urological and orthopaedic sequelae. Fetal surgical repair of myelomeningocele has been associated with improved early neurological outcome compared with postnatal operation. Myelomeningocele affects quality of life during childhood, adolescence and adulthood, posing a challenge for individuals, families and society as a whole. For an illustrated summary of this Primer, visit: http://go.nature.com/fK9XNa.
authors.affiliation: Newlife Birth Defects Research Centre, University College London Institute of Child Health, 30 Guilford Street, London WC1N 1EH, UK.
authors.forename: Andrew J
authors.initials: AJ
authors.lastname: Copp
authors.affiliation: Department of Surgery, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA.
authors.forename: N Scott
authors.initials: NS
authors.lastname: Adzick
authors.affiliation: Genetics and Genomic Medicine, University College London (UCL) Institute of Child Health, Great Ormond Street Hospital for Children NHS Foundation Trust and UCL Hospitals NHS Foundation Trust, London, UK.
authors.forename: Lyn S
authors.initials: LS
authors.lastname: Chitty
authors.affiliation: Department of Psychology, University of Houston, Houston, Texas, USA.
authors.forename: Jack M
authors.initials: JM
authors.lastname: Fletcher
authors.affiliation: Department of Psychology, Loyola University Chicago, Chicago, Illinois, USA.
authors.forename: Grayson N
authors.initials: GN
authors.lastname: Holmbeck
authors.affiliation: Department of Pediatrics, Stanford University School of Medicine, Stanford, California, USA.
authors.forename: Gary M
authors.initials: GM
authors.lastname: Shaw
mesh_terms: D005260:Female; D005492:Folic Acid / Q000627:therapeutic use; D006801:Humans; D008591:Meningomyelocele / Q000175:diagnosis / Q000517:prevention & control / Q000628:therapy; D011247:Pregnancy; D011295:Prenatal Care / Q000379:methods; D011296:Prenatal Diagnosis / Q000379:methods; D016135:Spinal Dysraphism / Q000175:diagnosis / Q000517:prevention & control / Q000628:therapy
chemical_list: D005492:Folic Acid