title: RORC2 Genetic Variants and Serum Levels in Patients with Rheumatoid Arthritis.
abstract: BACKGROUND
  In the present study, we aimed to evaluate whether polymorphisms within the RORc2 gene are involved in the risk and severity of rheumatoid arthritis (RA).
  
  
  METHODS
  591 RA patients and 341 healthy individuals were examined for RORc2 gene polymorphisms. Serum retinoic acid receptor-related orphan receptor C (RORc) levels were measured by enzyme-linked immunosorbent assay (ELISA).
  
  
  RESULTS
  The rs9826 A/G, rs12045886 T/C and rs9017 G/A RORc2 gene SNPs show no significant differences in the proportion of cases and control. Overall, rs9826 and rs9017 were in high linkage disequilibrium (LD) with D' = 0.952 and r² = 0.874, except rs9826 and rs12045886; and rs12045886 and rs9017 in weak LD. The genotype-phenotype analysis showed a significant association between RORc2 rs9826 A/G and rs9017 G/A single nucleotide polymorphisms (SNPs) and median of C-reactive protein (CRP). Serum RORc levels was higher in RA patients with rs9826AA, rs12045886TT and -TC, and rs9017AA genotypes compared to healthy subjects with the same genotypes (p = 0.02, p = 0.04 and p = 0.01, respectively). Moreover, the median of RORc protein level was higher in RA patients with number of swollen joints bigger then 3 (p = 0.04) and with Health Assessment Questionnaires (HAQ) score bigger then 1.5 (0.049).
  
  
  CONCLUSIONS
  Current findings indicated that the RORc2 genetic polymorphism and the RORc2 protein level may be associated with severity of RA in the Polish population.
authors.affiliation: Department of Biochemistry and Molecular Biology, National Institute of Geriatrics, Rheumatology and Rehabilitation, Spartańska 1, 02-637 Warsaw, Poland. paradowska_aga@interia.pl.
authors.forename: Agnieszka
authors.initials: A
authors.lastname: Paradowska-Gorycka
authors.affiliation: Department of Biochemistry and Molecular Biology, National Institute of Geriatrics, Rheumatology and Rehabilitation, Spartańska 1, 02-637 Warsaw, Poland. barbara.stypinska@wp.pl.
authors.forename: Barbara
authors.initials: B
authors.lastname: Stypinska
authors.affiliation: Department of Pharmacology, Pomeranian Medical University, 70-111 Szczecin, Poland. pawand@poczta.onet.pl.
authors.forename: Andrzej
authors.initials: A
authors.lastname: Pawlik
authors.affiliation: Department of Connective Tissue Diseases, National Institute of Geriatrics, Rheumatology and Rehabilitation, 02-637 Warsaw, Poland. katarzyna.prochnicka@gmail.com.
authors.forename: Katarzyna
authors.initials: K
authors.lastname: Romanowska-Prochnicka
authors.affiliation: Department of Connective Tissue Diseases, National Institute of Geriatrics, Rheumatology and Rehabilitation, 02-637 Warsaw, Poland. ehaladyj@o2.pl.
authors.forename: Ewa
authors.initials: E
authors.lastname: Haladyj
authors.affiliation: Department of Epidemiology and Health Promotion, National Institute of Geriatrics, Rheumatology and Rehabilitation, 02-637 Warsaw, Poland. m.manczak@op.pl.
authors.forename: Malgorzata
authors.initials: M
authors.lastname: Manczak
authors.affiliation: Department of Connective Tissue Diseases, National Institute of Geriatrics, Rheumatology and Rehabilitation, 02-637 Warsaw, Poland. marzena.olesinska@vp.pl.
authors.forename: Marzena
authors.initials: M
authors.lastname: Olesinska
mesh_terms: D000368:Aged; D001172:Arthritis, Rheumatoid / Q000097:blood / Q000453:epidemiology / Q000235:genetics* / Q000473:pathology; D005260:Female; D006239:Haplotypes; D006801:Humans; D008297:Male; D008875:Middle Aged; D057132:Nuclear Receptor Subfamily 1, Group F, Member 3 / Q000097:blood / Q000235:genetics*; D011044:Poland / Q000453:epidemiology; D020641:Polymorphism, Single Nucleotide; D012307:Risk Factors
chemical_list: D057132:Nuclear Receptor Subfamily 1, Group F, Member 3
keywords: RORc; Th17 cells; pathogenesis; polymorphisms; rheumatoid arthritis