A genetic variant in osteoprotegerin is associated with progression of joint destruction in rheumatoid arthritis.

Rachel Knevel,Diederik Pc De Rooy,Tore Saxne,Rene Em Toes,Elisabet Lindqvist,Martha K Leijsma,Roula Tsonaka,Tom Wj Huizinga,Joris Jm Schonkeren,Annette Hm Van Der Helm-Van Mil,Nina A Daha,Bobby Pc Koeleman,Jeanine J Houwing-Duistermaat,Anthony G Wilson,Elisabeth Brouwer

doi:10.1186/ar4558

Abstract

IntroductionProgression of joint destruction in rheumatoid arthritis (RA) is partly heritably; 45 to 58% of the variance in joint destruction is estimated to be explained by genetic factors. The binding of RANKL (Receptor Activator for Nuclear Factor κ B Ligand) to RANK results in the activation of TRAF6 (tumor necrosis factor (TNF) receptor associated factor-6), and osteoclast formation ultimately leading to enhanced bone resorption. This bone resorption is inhibited by osteoprotegerin (OPG) which prevents RANKL-RANK interactions. The OPG/RANK/RANKL/TRAF6 pathway plays an important role in bone remodeling. Therefore, we investigated whether genetic variants in OPG, RANK, RANKL and TRAF6 are associated with the rate of joint destruction in RA.Methods1,418 patients with 4,885 X-rays of hands and feet derived from four independent data-sets were studied. In each data-set the relative increase of the progression rate per year in the presence of a genotype was assessed. First, explorative analyses were performed on 600 RA-patients from Leiden. 109 SNPs, tagging OPG, RANK, RANKL and TRAF6, were tested. Single nucleotide polymorphisms (SNPs) significantly associated in phase-1 were genotyped in data-sets from Groningen (Netherlands), Sheffield (United Kingdom) and Lund (Switzerland). Data were summarized in an inverse weighted variance meta-analysis. Bonferonni correction for multiple testing was applied.ResultsWe found that 33 SNPs were significantly associated with the rate of joint destruction in phase-1. In phase-2, six SNPs in OPG and four SNPs in RANK were associated with progression of joint destruction with P-value <0.05. In the meta-analyses of all four data-sets, RA-patients with the minor allele of OPG-rs1485305 expressed higher rates of joint destruction compared to patients without these risk variants (P = 2.35x10−4). This variant was also significant after Bonferroni correction.ConclusionsThese results indicate that a genetic variant in OPG is associated with a more severe rate of joint destruction in RA.

Highlights

Progression of joint destruction in rheumatoid arthritis (RA) is partly heritably; 45 to 58% of the variance in joint destruction is estimated to be explained by genetic factors
We found that 33 Single nucleotide polymorphism (SNP) were significantly associated with the rate of joint destruction in phase-1
In phase-2, six SNPs in OPG and four SNPs in Receptor Activator for Nuclear Factor κ B (RANK) were associated with progression of joint destruction with P-value

Summary

Introduction

Progression of joint destruction in rheumatoid arthritis (RA) is partly heritably; 45 to 58% of the variance in joint destruction is estimated to be explained by genetic factors. The binding of RANKL (Receptor Activator for Nuclear Factor κ B Ligand) to RANK results in the activation of TRAF6 (tumor necrosis factor (TNF) receptor associated factor-6), and osteoclast formation leading to enhanced bone resorption. This bone resorption is inhibited by osteoprotegerin (OPG) which prevents RANKL-RANK interactions. We investigated whether genetic variants in OPG, RANK, RANKL and TRAF6 are associated with the rate of joint destruction in RA. RANKL promotes osteoclast formation and perpetuate their function and survival through binding of RANK (Receptor Activator of Nuclear Factor κ B). By binding of OPG to RANKL, activation of the RANK receptor is inhibited

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Results

Conclusion