Parental Origin, DNA Structure, and the Schizophrenia Spectrum

Abstract

Over the past 20 years, substantial evidence has accumulated that structural variations of the human genome, especially copy number variations, are important causal factors for schizophrenia and related disorders (1). Identification of associated copy number variations is shining new light on mechanisms of illness and on the genetically related spectrum of disorders (2) that may include not only bipolar disorder but also autism, mental retardation, and epilepsy (1). In this issue of the Journal, Ingason et al. (3) provide further data to suggest that neuropsychiatric conditions previously believed to be unconnected may share causal factors related to structural changes not visible on standard karyotype. Moreover, the parent of origin of the copy number variation in question, a duplication involving the proximal long (q) arm of chromosome 15, appears to be important.