We carried out a genome-wide association study of schizophrenia (479 cases, 2,937 controls) and tested loci with P < 10(-5) in up to 16,726 additional subjects. Of 12 loci followed up, 3 had strong independent support (P < 5 x 10(-4)), and the overall pattern of replication was unlikely to occur by chance (P = 9 x 10(-8)). Meta-analysis provided strongest evidence for association around ZNF804A (P = 1.61 x 10(-7)) and this strengthened when the affected phenotype included bipolar disorder (P = 9.96 x 10(-9)).

Abnormal oligodendrocyte function has been postulated as a primary etiological event in schizophrenia. Oligodendrocyte lineage transcription factor 2 (OLIG2) encodes a transcription factor central to oligodendrocyte development. Analysis of OLIG2 in a case-control sample (n ‫؍‬ Ϸ1,400) in the U.K. revealed several SNPs to be associated with schizophrenia (minimum P ‫؍‬ 0.0001, genewide P ‫؍‬ 0.0009). To obtain independent support for this association, we sought evidence for genetic interaction between OLIG2 and three genes of relevance to oligodendrocyte function for which we have reported evidence for association with schizophrenia: CNP, NRG1, and ERBB4. We found interaction effects on disease risk between OLIG2 and CNP (minimum P ‫؍‬ 0.0001, corrected P ‫؍‬ 0.008) for interaction with ERBB4 (minimum P ‫؍‬ 0.002, corrected P ‫؍‬ 0.04) but no evidence for interaction with NRG1. To investigate the biological plausibility of the interactions, we sought correlations between the expression of the genes. The results were similar to those of the genetic interaction analysis. OLIG2 expression significantly correlated in cerebral cortex with CNP (P < 10 ؊7 ) and ERBB4 (P ‫؍‬ 0.002, corrected P ‫؍‬ 0.038) but not NRG1. In mouse striatum, Olig2 and Cnp expression also was correlated, and linkage analysis for trans-effects on gene expression suggests that each locus regulates the other's expression. Our data provide strong convergent evidence that variation in OLIG2 confers susceptibility to schizophrenia alone and as part of a network of genes implicated in oligodendrocyte function. association ͉ oligodentrocyte͞myelin-related genes S chizophrenia is a major psychiatric disorder characterized by disturbances of perception, emotion, social functioning, and cognition. Its etiology includes a strong heritable component (1), but despite some successes in identifying susceptibility genes (2) the fundamental pathophysiology remains uncertain.Global surveys of mRNA expression can offer insights into potential pathophysiological pathways, even in tissues as complex as postmortem human brain. A prominent example is the identification of altered expression of ERBB3 in schizophrenia by independent groups (3-5), a finding of likely pathophysiological relevance given that its ERBB3 is one of two receptors that directly bind neuregulin 1, whose cognate gene (NRG1) is strongly implicated as a susceptibility gene for schizophrenia (2, 6).One of the most widely replicated groups of genes with altered expression in schizophrenia relate to oligodendrocyte function and myelination, oligodendrocytes being the myelinating cells in the brain (3)(4)(5)(7)(8)(9)(10)(11)(12). These data are compatible with the considerable evidence for altered myelination and oligodendrocyte function in schizophrenia (13). There is therefore a strong rationale to target for genetic analysis oligodendrocyte͞myelination related (OMR) genes. Here, we report strong data concerning a key OMR target, oligodendrocyte lineage transcription factor 2 (OLIG2).OLIG2 is a basi...

Our data support the hypothesis that reduced CNP expression in the schizophrenic brain is relevant to disease etiology and therefore provide support for the general hypothesis that altered oligodendrocyte function is an etiological factor in schizophrenia.

Neuregulin and the neuregulin receptor ERBB4 have been genetically and functionally implicated in schizophrenia. In this study, we used the yeast two-hybrid system to identify proteins that interact with ERBB4, to identify genes and pathways that might contribute to schizophrenia susceptibility. We identified the MAGI scaffolding proteins as ERBB4-binding proteins. After validating the interaction of MAGI proteins with ERBB4 in mammalian cells, we demonstrated that ERBB4 expression, alone or in combination with ERBB2 or ERBB3, led to the tyrosine phosphorylation of MAGI proteins, and that this could be further enhanced with receptor activation by neuregulin. As MAGI proteins were previously shown to interact with receptor phosphotyrosine phosphatase b/f (RPTPb), we postulated that simultaneous binding of MAGI proteins to RPTPb and ERBB4 forms a phosphotyrosine kinase/phosphotyrosine phosphatase complex. Studies in cultured cells confirmed both a spatial and functional association between ERBB4, MAGI and RPTPb. Given the evidence for this functional association, we examined the genes coding for MAGI and RPTPb for genetic association with schizophrenia in a Caucasian United Kingdom case-control cohort (n = B1400). PTPRZ1, which codes for RPTPb, showed significant, gene-wide and hypothesis-wide association with schizophrenia in our study (best individual single-nucleotide polymorphism allelic P = 0.0003; gene-wide P = 0.0064; hypothesiswide P = 0.026). The data provide evidence for a role of PTPRZ1, and for RPTPb signaling abnormalities, in the etiology of schizophrenia. Furthermore, the data indicate a role for RPTPb in the modulation of ERBB4 signaling that may in turn provide further support for an important role of neuregulin/ERBB4 signaling in the molecular basis of schizophrenia.

Several groups have reported an association between the 10-repeat allele of a dopamine transporter (DAT1) 3'UTR VNTR variant and ADHD but the finding has not been universally observed. An association between DAT1 genotype and stimulant medication response has also been reported although again there are conflicting data. We tested the DAT1 3'VNTR and three SNPs in the putative promoter region of DAT1 for association with ADHD in 263 parent-proband trios. Analyses of genotypes, alleles, and haplotypes were performed using family-based association methods. Case-control analysis of the VNTR in 263 cases and 287 controls was also conducted. In addition, we tested for association between the VNTR marker and stimulant medication response. Comparing allele 10 versus all other alleles combined, no significant association was found with ADHD, using FBAT analysis (chi2 = 0.1 (df 1), P = 0.9, (odds ratio (OR) = 1.0, 95% CI 0.8-1.2), and case-control analysis (chi2 = 0.12 (df 2), P = 0.91). No evidence of association with any of the SNPs in the promoter region was found. Haplotype analysis was also non-significant (chi2 = 3.93, (df 9) global P = 0.85). Finally, no association was found between the DAT 1 VNTR and response to stimulant medication (chi2 = 1.63 (df 3) P = 0.65). We conclude that the 3' VNTR and three additional promoter variants in DAT1 do not appear to be associated with ADHD, or response to stimulant mediation in our sample.