Rheumatoid Arthritis: Mosher D

Li LC, Badley EM, MacKay C, Mosher D, Jamal SW, Jones A, Bombardier C. · University of British Columbia and Arthritis Research Centre of Canada, 895 West 10th Avenue, Vancouver, BC, Canada. · Arthritis Rheum. · Pubmed #18668611 No free full text.

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Walker EJ, Hirschfield GM, Xu C, Lu Y, Liu X, Lu Y, Coltescu C, Wang K, Newman WG, Bykerk V, Keystone EC, Mosher D, Amos CI, Heathcote EJ, Siminovitch KA. · University of Toronto, Toronto General Hospital, and Mount Sinai Hospital, Toronto, Ontario, Canada. · Arthritis Rheum. · Pubmed #19333938 No free full text.

Abstract: OBJECTIVE: The co-occurrence of different autoimmune diseases in patients and their families suggests the presence of shared genetic risk factors. Two compelling candidate autoimmune disease susceptibility genes are those that encode CTLA4 and inducible costimulator (ICOS), immunoregulatory proteins. Associations of CTLA4 polymorphisms with various autoimmune diseases have been reported, but for rheumatoid arthritis (RA) and primary biliary cirrhosis (PBC), the association data are inconsistent and have largely excluded analysis of polymorphisms in the ICOS gene adjacent to CTLA4. We undertook this study to examine whether CTLA4 and ICOS influence RA and PBC susceptibility by testing CTLA4/ICOS polymorphisms for association with these diseases in Canadian subjects. METHODS: Caucasian RA patients (n = 1,140), PBC patients (n = 481), and controls (n = 1,248) were typed for 21 biallelic polymorphisms across the CTLA4/ ICOS genes using a multiplex genotyping array, and the results were analyzed using a false discovery rate method to correct for multiple testing. RESULTS: Significant associations of multiple CTLA4 and ICOS gene polymorphisms with RA and PBC were observed, with the strongest association signals for both diseases coming from a CTLA4/ICOS intergenic single-nucleotide polymorphism, rs17268364 (corrected P [P(corr)] = 6.0 x 10(-4) and P(corr) < 1.0 x 10(-4), respectively). Significant associations, which were common to both diseases, were also observed with other alleles and haplotypes across 3 linkage disequilibrium blocks within the CTLA4 gene, the intergenic region, and the ICOS gene. CONCLUSION: Our results provide evidence for RA and PBC association with the CTLA4/ICOS locus and suggest that the risk allele(s) within this region may be common to both diseases.

van Oene M, Wintle RF, Liu X, Yazdanpanah M, Gu X, Newman B, Kwan A, Johnson B, Owen J, Greer W, Mosher D, Maksymowych W, Keystone E, Rubin LA, Amos CI, Siminovitch KA. · Ellipsis Biotherapeutics Corporation, Toronto, Ontario, Canada. · Arthritis Rheum. · Pubmed #15986374 links to  free full text

Abstract: OBJECTIVE: A single-nucleotide polymorphism in the PTPN22 gene encoding the lymphoid protein tyrosine phosphatase (Lyp) has recently been identified as a functional variant associated with susceptibility to rheumatoid arthritis (RA), type 1 diabetes, and systemic lupus erythematosus. To determine whether association of this variant (PTPN22 1858T) with RA is reproducible and is also observed in another autoimmune condition, Crohn's disease, we investigated the association between the PTPN22 1858T allele and RA and Crohn's disease in a Canadian population. METHODS: Two RA case-control cohorts representing a total of 1,234 patients and 791 healthy controls as well as a cohort of 455 patients with Crohn's disease and 190 controls were genotyped for the PTPN22 C1858T polymorphism, and genotype frequencies were compared between patients and controls. RESULTS: Significant association of the PTPN22 1858T allele with RA was detected in both the Toronto-based RA cohort (P = 1.6 x 10(-6), odds ratio [OR] 1.8) and the Halifax-based RA cohort (P = 9.4 x 10(-4), OR 1.94). Association of the risk allele with RA was not affected by sex, age at disease onset, or the presence of either rheumatoid factor or rheumatoid nodules. No association between the PTPN22 risk allele and Crohn's disease was detected. CONCLUSION: These observations confirm the association of RA susceptibility with the PTPN22 1858T allele. However, the data also reveal a lack of association between this variant and Crohn's disease, suggesting that the PTPN22 1858T allele is a risk allele for multiple, but not all, autoimmune diseases.