Transancestral mapping of the MHC region in systemic lupus erythematosus identifies new independent and interacting loci at MSH5, HLA-DPB1 and HLA-G

OBJECTIVES: Systemic lupus erythematosus (SLE) is a chronic multisystem genetically complex autoimmune disease characterised by the production of autoantibodies to nuclear and cellular antigens, tissue inflammation and organ damage. Genome-wide association studies have shown that variants within the major histocompatibility complex (MHC) region on chromosome 6 confer the greatest genetic risk for SLE in European and Chinese populations. However, the causal variants remain elusive due to tight linkage disequilibrium across disease-associated MHC haplotypes, the highly polymorphic nature of many MHC genes and the heterogeneity of the SLE phenotype. METHODS: A high-density case-control single nucleotide polymorphism (SNP) study of the MHC region was undertaken in SLE cohorts of Spanish and Filipino ancestry using a custom Illumina chip in order to fine-map association signals in these haplotypically diverse populations. In addition, comparative analyses were performed between these two datasets and a northern European UK SLE cohort. A total of 1433 cases and 1458 matched controls were examined. RESULTS: Using this transancestral SNP mapping approach, novel independent loci were identified within the MHC region in UK, Spanish and Filipino patients with SLE with some evidence of interaction. These loci include HLA-DPB1, HLA-G and MSH5 which are independent of each other and HLA-DRB1 alleles. Furthermore, the established SLE-associated HLA-DRB1*15 signal was refined to an interval encompassing HLA-DRB1 and HLA-DQA1. Increased frequencies of MHC region risk alleles and haplotypes were found in the Filipino population compared with Europeans, suggesting that the greater disease burden in non-European SLE may be due in part to this phenomenon. CONCLUSION: These data highlight the usefulness of mapping disease susceptibility loci using a transancestral approach, particularly in a region as complex as the MHC, and offer a springboard for further fine-mapping, resequencing and transcriptomic analysis

Polymorphisms of CD16A and CD32 Fcγ receptors and circulating immune complexes in Ménière's disease: a case-control study

<p>Abstract</p> <p>Background</p> <p>Autoimmune diseases with elevated circulating autoantibodies drive tissue damage and the onset of disease. The Fcγ receptors bind IgG subtypes modulating the clearance of circulating immune complexes (CIC). The inner ear damage in Ménière's disease (MD) could be mediated by an immune response driven by CIC. We examined single-nucleotide polymorphism (SNPs) in the CD16A and CD32 genes in patients with MD which may determine a Fcγ receptor with lower binding to CIC.</p> <p>Methods</p> <p>The functional CD16A (FcγRIIIa*559A > C, rs396991) and CD32A (FcγRIIa*519A > G, rs1801274) SNPs were analyzed using PCR-based TaqMan Genotyping Assay in two cohorts of 156 mediterranean and 112 Galicia patients in a case-control study. Data were analyzed by χ²with Fisher's exact test and Cochran-Armitage trend test (CATT). CIC were measured by ELISA for C1q-binding CIC.</p> <p>Results</p> <p>Elevated CIC were found in 7% of patients with MD during the intercrisis period. No differences were found in the allelic frequency for rs396991 or rs1801274 in controls subjects when they were compared with patients with MD from the same geographic area. However, the frequency of AA and AC genotypes of CD16A (rs396991) differed among mediterranean and Galicia controls (Fisher's test, corrected p = 6.9 × 10^-4for AA; corrected p = 0.02 for AC). Although genotype AC of the CD16A receptor was significantly more frequent in mediterranean controls than in patients, [Fisher's test corrected p = 0.02; OR = 0.63 (0.44-0.91)], a genetic additive effect for the allele C was not observed (CATT, p = 0.23). Moreover, no differences were found in genotype frequencies for rs396991 between patients with MD and controls from Galicia (CATT, p = 0.14). The allelic frequency of CD32 (rs1801274) was not different between patients and controls either in mediterranean (p = 0.51) or Galicia population (p = 0.11).</p> <p>Conclusions</p> <p>Elevated CIC are not found in most of patients with MD. Functional polymorphisms of CD16A and CD32 genes are not associated with onset of MD.</p

The Laryngoscope Association of a Functional Polymorphism of PTPN22 Encoding a Lymphoid Protein Phosphatase in Bilateral Meniere&apos;s Disease

Objectives/Hypothesis: Bilateral Meniere&apos;s disease (BMD) is a severe disease that usually results in bilateral severe or profound sensorineural hearing loss and chronic disequilibrium with loss of vestibular function. We examined single nucleotide polymorphisms (SNPs) in the PTPN22 and CTLA4 genes in Caucasian patients with BMD to assess the possible association between these polymorphism and the predisposition and clinical expression of this disease. Study Design: A case control study. Methods: The functional protein tyrosine phosphatase type 22 (PTPN22) SNP (rs2476601, 1858C/T) and CTLA4 SNP (rs231775, 49A/G) were analyzed in 52 patients with BMD and 348 healthy controls by a TaqMan 5 0 allelic discrimination assay. Data were analyzed by a v 2 test with Fisher exact test. Results: No association was found between the þ49A/G CTLA4 genotype and BMD patients. However, the heterozygote PTPN22 1858C/T genotype was present at a significantly higher frequency in BMD patients than in controls (odds ratio ¼ 2.25, 95% confidence interval: 1.09-4.62; P ¼ .04). Conclusions: These results suggest that the PTPN22 1858C/T genotype may confer differential susceptibility to BMD in the Spanish population and support an autoimmune etiology for BMD

Functional Variants in NOS1 and NOS2A Are Not Associated with Progressive Hearing Loss in Ménière's Disease in a European Caucasian Population

This is a copy of an article published in the DNA and Cell Biology © 2011 [copyright Mary Ann Liebert, Inc.]; DNA and Cell Biology is available online at: http://online.liebertpub.com.Hearing loss in Meniere's disease (MD) is associated with loss of spiral ganglion neurons and hair cells. In a guinea pig model of endolymphatic hydrops, nitric oxide synthases (NOS) and oxidative stress mediate loss of spiral ganglion neurons. To test the hypothesis that functional variants of NOS1 and NOS2A are associated with MD, wed genotyped three functional variants of NOS1 (rs41279104,rs2682826, and a cytosine-adenosine microsatellite repeat in exon 1f) and the CCTTT repeat in the promoter of NOS2A gene (rs3833912) in two independent MD sets(273 patients in total) and 550 controls. A third cohort of American patients was genotyped as replication cohort for the CCTTT repeat. Neither allele nor genotype frequencies of rs41279104 and rs2682826 were associated with MD, although longer alleles of the cytosine-adenosine microsatellite repeat were marginally significant (corrected p = 0.05) in the Mediterranean cohort but not in a second Galicia cohort. Shorter numbers of the CCTTT repeat in NOS2A were significantly more frequent in Galicia controls (OR = 0.37 [CI, 0.18-0.76], corrected p =0.04), but this finding could not be replicated in Mediterranean or American case-control populations. Meta-analysis did not support an association between CCTTT repeats and risk for MD. Severe hearing loss (>75 dB) was also not associated with any functional variants studied. Functional variants of NOS1 and and NOS2A do not confer susceptibility for MD.This study was funded by an FIS PI10/0920 Research Project from ISCIII. J.A.L.-E. was partially supported by ISCIII research grant INT09/229. The 3130 XL Genetics Analyzer was funded by grant IF06/37291 from Ministry of Science. This work was partially supported by the University of Iowa, Department of Otolaryngology and the Research Fund of the American Otological Society (to R.J.H.S.).Ye

MY09B gene polymorphisms are associated with autoimmune diseases in Spanish population

The aim of the study was to test MYO9B gene polymorphisms for association with three autoimmune diseases, systemic lupus erythematosus (SLE), rheumatoid arthritis (RA), and celiac disease (CD), in a Spanish population. We analyzed three SNPs (rs2305767, rs1457092, and rs2305764) in a case-control cohort composed of 349 SLE patients, 356 RA patients, 90 CID patients, and 345 healthy controls. All three SNPs showed a consistent increased frequency of the A allele in SLE, RA, and CID patients compared with healthy controls. An association was observed between CID and rs2305764 (p = 0.01, OR = 2.3), between SLE and rs1457092 (p = = 0.002, OR = 1.4), and between RA and rs1457092 (p = 0.02, OR = 1.3). The three autoimmune diseases combined showed significant association with rs1457092 and rs2305764 and with the AAA haplotype (p haplotype = 0.005, OR = 1.3). Our data demonstrate consistent association with the A allele and AAA haplotype of three SNPs in the MYO9B gene, which were previously reported to be associated with CD in the Dutch population. This suggests that genetic variation in MYO9B is associated with CID, SLE, and RA and that MYO9B is a general risk factor for autoimmunity. (c) 2007 American Society for Histocompatibility and Immunogenetics. Published by Elsevier Inc. All rights reserved