title: Linkage disequilibrium patterns and functional analysis of RGS4 polymorphisms in relation to schizophrenia.
abstract: The regulator of G-protein signaling 4 (RGS4, chromosome 1q23.3) plays a critical role in G-protein function. Four common single-nucleotide polymorphisms (SNPs) localized between the 5' upstream sequence and the first intron, as well as 2 haplotypes derived from these SNPs may confer liability to schizophrenia (SZ). However, the pattern of associations varies among samples. To help clarify the putative associations, we report the following analyses: (1) a comprehensive catalog of common polymorphisms, (2) linkage disequilibrium (LD) and association analyses using these SNPs, and (3) functional analysis based on dual-luciferase promoter assays. We identified 62 SNPs from a 20-kb genomic region spanning RGS4, of which 26 are common polymorphisms with a minor allele frequency (MAF) of >5%. LD analysis suggested 5 clusters of SNPs (r(2) > .8). Association analyses using the novel SNPs were consistent with the prior reports, but further localization was constrained by significant LD across the region. The 2 haplotypes reported to confer liability to SZ had significant promoter activity compared with promoterless constructs, suggesting a functional role for both haplotypes. Further analyses of promoter sequences are warranted to understand transcriptional regulation at RGS4. This information will be useful for further analysis of samples in which genetic association of RGS4 polymorphisms with SZ has been reported.
authors.affiliation: Department of Psychiatry, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA.
authors.forename: Kodavali V
authors.initials: KV
authors.lastname: Chowdari
authors.forename: Mikhil
authors.initials: M
authors.lastname: Bamne
authors.forename: Joel
authors.initials: J
authors.lastname: Wood
authors.forename: Michael E
authors.initials: ME
authors.lastname: Talkowski
authors.forename: Karoly
authors.initials: K
authors.lastname: Mirnics
authors.forename: Pat
authors.initials: P
authors.lastname: Levitt
authors.forename: David A
authors.initials: DA
authors.lastname: Lewis
authors.forename: Vishwajit L
authors.initials: VL
authors.lastname: Nimgaonkar
mesh_terms: D005091:Exons / Q000235:genetics; D005838:Genotype; D006239:Haplotypes / Q000235:genetics; D006801:Humans; D007438:Introns / Q000235:genetics; D015810:Linkage Disequilibrium / Q000235:genetics*; D020641:Polymorphism, Single Nucleotide / Q000235:genetics*; D020710:RGS Proteins / Q000235:genetics*; D012559:Schizophrenia / Q000235:genetics*
chemical_list: D020710:RGS Proteins; C098799:RGS4 protein