| 1 | Am. J. Med. Genet. B Neuropsychiatr. Genet. 2003 Feb 117B: 51-6 |
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| PMID | 12555235 |
| Title | Association of EEG coherence and an exonic GABA(B)R1 gene polymorphism. |
| Abstract | The GABA(B) receptor 1 gene is mapped to chromosome 6p21.3 within the HLA class I region close to the HLA-F gene. Susceptibility loci for epilepsy and schizophrenia have been mapped in this region. Based on pharmacological evidence, it has been suggested that GABA(B) receptors may play a crucial role in the synchronization of EEG oscillations, which in turn can be abnormal in neuropsychiatric disorders. In the present study, the hypothesis was tested, whether three exonic variants of the gene encoding the human GABA(B) receptor (GABA(B)R1) modify cortical synchronization measured as scalp-recorded EEG-coherence. Two principal components of EEG coherence (frontal coherence, parietotemporal coherence) were investigated in 104 healthy subjects during three conditions: resting EEG, activated EEG, and event-related EEG. No significant associations were found between the frontal coherence component and any polymorphism or between the parietotemporal coherence component and the exon 1a1 polymorphism. However, parietotemporal coherence showed statistically highly significant associations across all three experimental conditions with exon 7 and trend associations with exon 11. The results provide evidence that the translated polymorphism of exon 7 may be functionally meaningful and impact cortical EEG oscillations. Since variations of EEG coherence have been described for several neuropsychiatric disorders, the present association should be tested in clinical samples using EEG coherence as an intermediate phenotype. |
| SCZ Keywords | schizophrenia |
| 2 | Am. J. Med. Genet. B Neuropsychiatr. Genet. 2014 Jul 165B: 421-7 |
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| PMID | 24888570 |
| Title | Replication and cross-phenotype study based upon schizophrenia GWASs data in the Japanese population: support for association of MHC region with psychosis. |
| Abstract | Recent genome-wide association studies (GWASs) of schizophrenia (SCZ) identified several susceptibility genes and suggested shared genetic components between SCZ and bipolar disorder (BD). We conducted a genetic association study of single nucleotide polymorphisms (SNPs) selected according to previous SCZ GWAS targeting psychotic disorders (SCZ and BD) in the Japanese population. Fifty-one SNPs were analyzed in a two-stage design using first-set screening samples (all SNPs: 1,032 SCZ, 1,012 BD, and 993 controls) and second-set replication samples ("significant" SNPs in the first-set screening analysis: 1,808 SCZ, 821 BD, and 2,321 controls). We assessed allelic associations between the selected SNPs and the three phenotypes (SCZ, BD, and "psychosis" [SCZ?+?BD]). Nine SNPs revealed nominal association signals for all comparisons (P(uncorrected)?HLA-F antisense RNA1 [HLA-F-AS1]) were further assessed in the second-set replication samples. The associations were confirmed for rs7759855 (P(corrected)?=?0.026 for psychosis; P(corrected)?=?0.032 for SCZ), although the direction of effect was opposite to that in the original GWAS of the Chinese population. Finally, a meta-analysis was conducted using our two samples and using our data and data from Psychiatric GWAS Consortium (PGC), which have shown the same direction of effect. SNP in ZSCAN31 (rs7759855) had the strongest association with the phenotypes (best P?=?6.8?×?10(-5) for psychosis: present plus PGC results). These data support shared risk SNPs between SCZ and BD in the Japanese population and association between MHC and psychosis. |
| SCZ Keywords | schizophrenia |