Study Report

Reference	Bergen, S. E.,2012 PMID: 22688191
Citation	Bergen, S. E., C. T. O'Dushlaine, et al. (2012). "Genome-wide association study in a Swedish population yields support for greater CNV and MHC involvement in schizophrenia compared with bipolar disorder." Mol Psychiatry.
Disease Type	Bipolar Disorder & Schizophrenia
Study Design	case-control
Study Type	Genome-wide association study
Sample Size	1507 SCZ cases, 836 BD cases and 2093 controls
SNP/Region/Marker Size	745,006 SNPs
Predominant Ethnicity	Caucasian
Population	Swedish
Age Group	Adults

Sample Diagnosis	DSM
Sample Status	Schizophrenia. Comprehensive analyses of most SCZ cases (N=1507) and controls (N=2093) are newly reported here, and some SCZ cases (N=560) and controls (N=400) from this study have been reported previously. Additionally, 44 SCZ cases and 42 controls previously removed from analyses owing to Finnish ancestry were reintegrated into the current analyses. All subjects were born in Sweden, and SCZ cases were identified via the Swedish Hospital Discharge Register containing all individuals hospitalized in Sweden since 1973.Bipolar disorder. The previously unreported BD subjects (N=836) were only collected in the most recent recruitment wave through three channels. Some BD cases (N=256) were identified using the Swedish Hospital Discharge Register with at least two hospitalizations with a BD diagnosis and confirmatory diagnostic review in a subset of subjects.Additional subjects were recruited from the Affective Center at St Goran Hospital in Stockholm, Sweden, following physician's referral for BD(N=216). The diagnostic instrument used was a Swedish adaptation of the Affective Disorder Evaluation,which includes the affective module of the Structured Clinical Interview for DSM-IV.A further 571 BD cases were recruited from the Stockholm County catchment area. Diagnoses were made according to the DSM-IV criteria, and cases were not reported previously. The control subjects used were the same as for the SCZ analyses described above.
Technique	Genotyping by Affymetrix 6.0 chips
Statistical Method	All association analyses were conducted using logistic regression in PLINK.We used a genome-wide significance threshold of P<5E-08.
Result Summary	No single-nucleotide polymorphisms (SNPs) achieved significance in these new samples; however, combining new and previously reported SCZ samples (2111 SCZ and 2535 controls) revealed a genome-wide significant association in the major histocompatibility complex (MHC) region (rs886424, P=4.54 x 10(-8)).