Associations of Independent IL2RA Gene Variants with Intermediate Uveitis
PLOS ONE
Authors: Lindner, Ewald; Weger, Martin; Ardjomand, Navid; Renner, Wilfried; El-Shabrawi, Yosuf
Abstract
Purpose The genetic background for the concomitance of uveitis and other autoimmune diseases remains elusive. Here the role of two IL2RA gene variants (rs11594656 and rs12722495) was investigated in intermediate uveitis and HLAB27 acute anterior uveitis. Materials and Methods One hundred fifty-nine patients with HLAB27 acute anterior uveitis, 85 patients with intermediate uveitis, 138 HLAB27 negative controls and 100 HLAB27 positive controls were recruited for this case-control study. Main outcome measures were genotype distribution and allelic frequencies determined by polymerase chain reaction. Results The frequencies of carriers of the minor allele at rs11594656 and rs12722495 were significantly different in patients with intermediate uveitis compared to HLAB27 positive and negative controls combined (p<0.05). For rs12722495 the minor G allele was protective (genotypic OR: 0.29 [0.12-0.69]), and for rs11594656 the minor A allele conferred risk (genotypic OR: 1.59 [1.09-2.32]). No significant differences in genotype distribution were found between patients with HLAB27 acute anterior uveitis and HLAB27 positive or negative control subjects. Conclusions We found rs11594656 and rs12722495 to be associated with intermediate uveitis but not with HLAB27 acute anterior uveitis. The genetic heterogeneity found at the IL2RA locus could help explain patterns of concomitance with other autoimmune diseases.
1000 Genomes-based imputation identifies novel and refined associations for the Wellcome Trust Case Control Consortium phase 1 Data
EUROPEAN JOURNAL OF HUMAN GENETICS
Authors: Huang, Jie; Ellinghaus, David; Franke, Andre; Howie, Bryan; Li, Yun
Abstract
We hypothesize that imputation based on data from the 1000 Genomes Project can identify novel association signals on a genome-wide scale due to the dense marker map and the large number of haplotypes. To test the hypothesis, the Wellcome Trust Case Control Consortium (WTCCC) Phase I genotype data were imputed using 1000 genomes as reference (20100804 EUR), and seven case/control association studies were performed using imputed dosages. We observed two 'missed' disease-associated variants that were undetectable by the original WTCCC analysis, but were reported by later studies after the 2007 WTCCC publication. One is within the IL2RA gene for association with type 1 diabetes and the other in proximity with the CDKN2B gene for association with type 2 diabetes. We also identified two refined associations. One is SNP rs11209026 in exon 9 of IL23R for association with Crohn's disease, which is predicted to be probably damaging by PolyPhen2. The other refined variant is in the CUX2 gene region for association with type 1 diabetes, where the newly identified top SNP rs1265564 has an association P-value of 1.68 x 10(-16). The new lead SNP for the two refined loci provides a more plausible explanation for the disease association. We demonstrated that 1000 Genomes-based imputation could indeed identify both novel (in our case, 'missed' because they were detected and replicated by studies after 2007) and refined signals. We anticipate the findings derived from this study to provide timely information when individual groups and consortia are beginning to engage in 1000 genomes-based imputation. European Journal of Human Genetics (2012) 20, 801-805; doi: 10.1038/ejhg.2012.3; published online 1 February 2012