A pediatric twin study of brain morphometry.
BACKGROUND
Longitudinal pediatric neuroimaging studies have demonstrated increasing volumes of white matter and regionally-specific inverted U shaped developmental trajectories of gray matter volumes during childhood and adolescence. Studies of monozygotic and dyzygotic twins during this developmental period allow exploration of genetic and non-genetic influences on these developmental trajectories.


METHODS
Magnetic resonance imaging brain scans were acquired on a pediatric sample of 90 monozygotic twin pairs, 38 same-sex dyzygotic twin pairs, and 158 unrelated typically developing singletons. Structural equation modeling was used to estimate the additive genetic, common environment, and unique environment effects, as well as age by heritability interactions, on measures of brain volumes from these images.


RESULTS
Consistent with previous adult studies, additive genetic effects accounted for a substantial portion of variability in nearly all brain regions with the notable exception of the cerebellum. Significant age by heritability interactions were observed with gray matter volumes showing a reduction in heritability with increasing age, while white matter volume heritability increased with greater age.


CONCLUSIONS
Understanding the relative contributions of genetic and nongenetic factors on developmental brain trajectories may have implications for better understanding brain-based disorders and typical cognitive development.
Wallace
Gregory L
GL
Child Psychiatry Branch, National Institute of Mental Health, Bethesda, MD, USA.
Eric Schmitt
J
J
Lenroot
Rhoshel
R
Viding
Essi
E
Ordaz
Sarah
S
Rosenthal
Michael A
MA
Molloy
Elizabeth A
EA
Clasen
Liv S
LS
Kendler
Kenneth S
KS
Neale
Michael C
MC
Giedd
Jay N
JN
D000293:Adolescent; D002540:Cerebral Cortex / Q000033:anatomy & histology*; D002648:Child; D002657:Child Development / Q000502:physiology*; D004777:Environment; D006801:Humans; D008279:Magnetic Resonance Imaging; D010372:Pediatrics / Q000295:instrumentation*; D010641:Phenotype; D014427:Twins