Discordance of prenatal and neonatal brain development in twins.
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.
Mukherjee
Niyati
N
Department of Psychiatry, University of North Carolina School of Medicine, Chapel Hill, NC 27599-7160, USA.
Kang
Chaeryon
C
Wolfe
Honor M
HM
Hertzberg
Barbara S
BS
Smith
J Keith
JK
Lin
Weili
W
Gerig
Guido
G
Hamer
Robert M
RM
Gilmore
John H
JH
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