Another valuable approach for identifying disease genes is the identification of chromosomal aberrations in patients. Translocations, duplications or deletions of large chromosome segments can be visualized by karyotyping or fluorescence in situ hybridization (FISH). Newer methods for detection of duplications or deletions ranging from ~1kb to several Mb in size, referred to as copy number variations (CNVs), have identified de novo and inherited CNVs associated with risk of many neuropsychiatric disorders [61–65].
