The chromosomal regions that harbor CNVs observed to be associated with psychiatric disorder are located at multiple genomic regions on many different chromosomes, and each deletion or duplication often encompasses several genes. So, are these simply randomly distributed mutations, or are their locations significant? Multiple types of evidence suggest that CNV locations provide meaningful clues to the neurobiology of these disorders. Genes code for proteins that are involved in different biological processes. The functions of different genetic elements are not fully understood; however, genetic findings can be used to make inferences about the biological processes involved. Although there are some methodological limitations to this approach, consistent patterns of findings are emerging. The rare CNVs found to be associated with ASD, ADHD, schizophrenia, and ID all seem to span genes that converge on meaningful biological processes. For example, CNV studies of ASD, schizophrenia, and ID have strongly implicated disrupted synaptic function. Studies of ADHD have suggested involvement of nicotinic acetylcholine receptor pathways, glutamatergic transmission (also found in schizophrenia), and genes involved in neural development.
