title: Schizencephaly prevalence, prenatal diagnosis and clues to etiology: a register-based study.
abstract: OBJECTIVE
  To establish the prevalence and antenatal diagnosis of schizencephaly in the UK.
  
  
  METHODS
  Data on schizencephaly were extracted from six regional congenital anomaly registers.
  
  
  RESULTS
  Thirty-eight cases of schizencephaly were identified in 2 567 165 livebirths and stillbirths, giving a total prevalence of 1.48/100 000 births (95% CI, 1.01-1.95). Eighteen (47% (95% CI, 31-63%)) of the 38 cases were identified antenatally. No affected fetus had an abnormal karyotype identified. A high proportion of cases of schizencephaly occurred in younger mothers: 63% were aged 24 years or less, significantly higher (P < 0.0001) than the corresponding proportion (26%) of mothers in England and Wales. The majority of cases were not identified until after 22 weeks of pregnancy. Additional anomalies associated with vascular disruption sequences were found in eight cases which had septo-optic dysplasia or absent septum pellucidum, one of which also had gastroschisis.
  
  
  CONCLUSIONS
  Schizencephaly occurs more frequently in the fetuses of younger mothers. It is often associated with septo-optic dysplasia, suggesting that the two conditions may share a common origin, arising as a result of destructive processes that cause changes in the brain which only become apparent on ultrasound in the second half of pregnancy.
authors.affiliation: Wessex Fetal Medicine Unit, Princess Anne Hospital, Southampton, UK. dth@soton.ac.uk
authors.forename: D T
authors.initials: DT
authors.lastname: Howe
authors.forename: J
authors.initials: J
authors.lastname: Rankin
authors.forename: E S
authors.initials: ES
authors.lastname: Draper
mesh_terms: D000293:Adolescent; D000328:Adult; D017677:Age Distribution; D003586:Cytomegalovirus Infections / Q000150:complications / Q000175:diagnosis* / Q000453:epidemiology; D004739:England / Q000453:epidemiology; D005260:Female; D006801:Humans; D013287:Illicit Drugs / Q000009:adverse effects*; D007231:Infant, Newborn; D007621:Karyotyping; D008279:Magnetic Resonance Imaging; D008297:Male; D054220:Malformations of Cortical Development / Q000175:diagnosis* / Q000453:epidemiology / Q000209:etiology; D008423:Maternal Age; D011247:Pregnancy; D011256:Pregnancy Outcome; D011296:Prenatal Diagnosis; D015995:Prevalence; D012042:Registries; D019966:Substance-Related Disorders / Q000150:complications / Q000175:diagnosis* / Q000453:epidemiology; D016216:Ultrasonography, Prenatal; D055815:Young Adult
chemical_list: D013287:Illicit Drugs