Age-related changes in heritability may be linked to the timing of gene expression and related to the age of onset of disorders. In general, heritability increases with age for WM and decreases for GM volumes (Wallace et al., 2006), whereas heritability increases for cortical thickness in regions within the frontal cortex, parietal, and temporal lobes (Lenroot et al., 2009). Knowledge of when certain brain structures are particularly sensitive to genetic or environmental influences during development could have important educational and/or therapeutic implications.
