Within the context of psychiatric genetic studies, “CNV” has come to be virtually synonymous with “rare variant.” In truth, structural variants come in many shapes, sizes and allele frequencies, and a majority of variants present in an individual genome are common alleles (Conrad et al., 2010; McCarroll et al., 2008; Mills et al., 2011; Sudmant et al., 2010). However, it is the rare CNVs that have garnered great attention (Sebat et al., 2009).
