title: Discordance of prenatal and neonatal brain development in twins.
abstract: BACKGROUND
  Discordance of birth weight has been observed in twin pairs, though little is known about prenatal and early neonatal discordance of head and brain size, and the role that zygosity and chorionicity play in discordances of early brain development in twins.
  
  
  OBJECTIVE
  To compare prenatal and neonatal discordances of head size in monozygotic-monochorionic (MZ-MC), monozygotic-dichorionic (MZ-DC), and same-sex dizygotic-dichorionic twin pairs (DZ).
  
  
  METHODS
  Subjects prospectively had ultrasounds at 22 and 32 weeks gestational age, and magnetic resonance imaging (MRI) of the brain MRI after birth.
  
  
  METHODS
  88 twin pairs recruited from two university hospital prenatal diagnostic clinics; 22 MZ-MC, 17 MZ-DC, and 49 same-sex DZ pairs.
  
  
  METHODS
  Discordance of head circumference (HC) and weight at 22 weeks, 32 weeks and birth, as well as intracranial volume (ICV) on neonatal MRI.
  
  
  RESULTS
  There were no group differences in discordance of head circumference and weight on the 22 or 32 week ultrasounds, or at birth. MZ-MC twins tended to have numerically greater discordances of HC and weight. There was a significant group difference in ICV on neonatal MRI (ANOVA, p=0.0143), with DZ twins having significantly greater discordance than MZ-MC (p=0.028) or MZ-DC (p=0.0131) twins.
  
  
  CONCLUSIONS
  This study indicates that zygosity and chorionicity do not contribute to significant discordances of head size in late prenatal development. DZ twins do have significantly greater discordances of ICV on neonatal MRI, suggesting a relatively greater genetic influence on brain growth in the first weeks after birth.
authors.affiliation: Department of Psychiatry, University of North Carolina School of Medicine, Chapel Hill, NC 27599-7160, USA.
authors.forename: Niyati
authors.initials: N
authors.lastname: Mukherjee
authors.forename: Chaeryon
authors.initials: C
authors.lastname: Kang
authors.forename: Honor M
authors.initials: HM
authors.lastname: Wolfe
authors.forename: Barbara S
authors.initials: BS
authors.lastname: Hertzberg
authors.forename: J Keith
authors.initials: JK
authors.lastname: Smith
authors.forename: Weili
authors.initials: W
authors.lastname: Lin
authors.forename: Guido
authors.initials: G
authors.lastname: Gerig
authors.forename: Robert M
authors.initials: RM
authors.lastname: Hamer
authors.forename: John H
authors.initials: JH
authors.lastname: Gilmore
mesh_terms: D001921:Brain / Q000033:anatomy & histology / Q000196:embryology* / Q000254:growth & development*; D002508:Cephalometry; D005260:Female; D006801:Humans; D007231:Infant, Newborn; D008279:Magnetic Resonance Imaging; D008297:Male