Oxford University Press, Schizophrenia Bulletin: The Journal of Psychoses and Related Disorders, 1(35), p. 96-108, 2008
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Background: Genome-wide association studies (GWASs) are increasingly used to identify risk genes for complex illnesses including schizophrenia. These studies may require thousands of subjects to obtain sufficient power. We present an alternative strategy with increased statistical power over a case-control study that uses brain imaging as a quantitative trait (QT) in the context of a GWAS in schizophrenia. Methods: Sixty-four subjects with chronic schizophrenia and 74 matched controls were recruited from the Functional Biomedical Informatics Research Network (FBIRN) consortium. Subjects were genotyped using the Illumina HumanHap300 BeadArray and were scanned while performing a Sternberg Item Recognition Paradigm in which they learned and then recognized target sets of digits in an functional magnetic resonance imaging protocol. The QT was the mean blood oxygen level–dependent signal in the dorsolateral prefrontal cortex during the probe condition for a memory load of 3 items. Results: Three genes or chromosomal regions were identified by having 2 single-nucleotide polymorphisms (SNPs) each significant at P