Heritability of brain ventricle volume: converging evidence from inconsistent results.
Twin studies generally show great consistency for the heritability of brain structures. Ironically, the lateral ventricles--perhaps the most reliably measured brain regions of interest--are the most inconsistent when it comes to estimating genetic influences on their volume. Heritability estimates in twin studies have ranged from zero to almost 0.80. Here we aggregate heritability estimates from extant twin studies, and we review and reinterpret some of the findings. Based on our revised estimates, we conclude that lateral ventricular volume is indeed heritable. The weighted average heritability of the revised estimates was 0.54. Although accumulated environmental insults might seem most logical as the predominant cause of age-related ventricular expansion, the data strongly suggest that genetic influences on lateral ventricular volume are increasing with age. Genetic influences accounted for 32-35% of the variance in lateral ventricular volume in childhood, but about 75% of the variance in late middle and older age. These conclusions have implications for the basic understanding of the genetic and environmental underpinnings of normative and pathological brain aging.
Kremen
William S
WS
Department of Psychiatry, University of California, San Diego, La Jolla, CA 92093, USA. wkremen@ucsd.edu
Panizzon
Matthew S
MS
Neale
Michael C
MC
Fennema-Notestine
Christine
C
Prom-Wormley
Elizabeth
E
Eyler
Lisa T
LT
Stevens
Allison
A
Franz
Carol E
CE
Lyons
Michael J
MJ
Grant
Michael D
MD
Jak
Amy J
AJ
Jernigan
Terry L
TL
Xian
Hong
H
Fischl
Bruce
B
Thermenos
Heidi W
HW
Seidman
Larry J
LJ
Tsuang
Ming T
MT
Dale
Anders M
AM
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000473:pathology; D002552:Cerebral Ventricles / Q000033:anatomy & histology* / Q000473:pathology*; D002648:Child; D059647:Gene-Environment Interaction; D006801:Humans; D008875:Middle Aged; D009929:Organ Size / Q000235:genetics*; D018401:Sample Size; D018433:Twin Studies as Topic; D055815:Young Adult