title: White matter heritability using diffusion tensor imaging in neonatal brains.
abstract: Understanding genetic and environmental effects on white matter development in the first years of life is of great interest, as it provides insights into the etiology of neurodevelopmental disorders. In this study, the genetic and environmental effects on white matter were estimated using data from 173 neonatal twin subjects. Diffusion tensor imaging scans were acquired around 40 days after birth and were non-rigidly registered to a group-specific atlas and parcellated into 98 ROIs. A model of additive genetic, and common and specific environmental variance components was used to estimate overall and regional genetic and environmental contributions to diffusion parameters of fractional anisotropy, radial diffusivity, and axial diffusivity. Correlations between the regional heritability values and diffusion parameters were also examined. Results indicate that individual differences in overall white matter microstructure, represented by the average diffusion parameters over the whole brain, are heritable, and estimates are higher than found in studies in adults. Estimates of genetic and environmental variance components vary considerably across different white matter regions. Significant positive correlations between radial diffusivity heritability and radial diffusivity values are consistent with regional genetic variation being modulated by maturation status in the neonatal brain: the more mature the region is, the less genetic variation it shows. Common environmental effects are present in a few regions that tend to be characterized by low radial diffusivity. Results from the joint diffusion parameter analysis suggest that multivariate modeling approaches might be promising to better estimate maturation status and its relationship with genetic and environmental effects.
authors.affiliation: Department of Psychiatry, University of North Carolina, Chapel Hill, NC, USA.
authors.forename: Xiujuan
authors.initials: X
authors.lastname: Geng
authors.forename: Elizabeth C
authors.initials: EC
authors.lastname: Prom-Wormley
authors.forename: Javier
authors.initials: J
authors.lastname: Perez
authors.forename: Thomas
authors.initials: T
authors.lastname: Kubarych
authors.forename: Martin
authors.initials: M
authors.lastname: Styner
authors.forename: Weili
authors.initials: W
authors.lastname: Lin
authors.forename: Michael C
authors.initials: MC
authors.lastname: Neale
authors.forename: John H
authors.initials: JH
authors.lastname: Gilmore
mesh_terms: D001724:Birth Weight; D001921:Brain / Q000033:anatomy & histology*; D056324:Diffusion Tensor Imaging; D005260:Female; D059647:Gene-Environment Interaction; D005865:Gestational Age; D006801:Humans; D007231:Infant, Newborn; D008297:Male; D019655:Quantitative Trait, Heritable; D014427:Twins / Q000235:genetics