Attention to developmental changes in and/or the developmental salience of particular genes for candidate endophenotypes may be important for identifying the relevant genes and gene networks implicated in AUD. Fully 95% of genes are expressed in the developing fetal brain [134], in contrast to the 84% of genes expressed in the adult human brain [135]. The structure and function of the brain is largely determined during prenatal development, with a second wave of development in adolescence [136]. Thus, the genes and gene networks that influence neuronal development, cellular migration, and brain anatomy and function may be predominantly expressed quite early in development, but their consequences for cognitive, neurophysiological, and functional brain candidate endophenotypes may only emerge later in development.
