A LRRC37A2 single nucleotide variant is associated with emphysema in Japanese patients with rheumatoid arthritis

Objective Extra-articular manifestations commonly complicate rheumatoid arthritis (RA) and include chronic lung diseases (CLD), for example, interstitial lung disease or emphysema (EMP). These confer a poor prognosis. Genetic studies of idiopathic pulmonary fibrosis (IPF) or EMP were conducted. However, there are limited genetic studies on EMP in RA. We examined whether a single nucleotide variant associated with susceptibility to IPF was associated to EMP in Japanese RA patients. Methods rs199526 [C/G] genotyping of LRRC37A2 in samples from 88 RA patients with EMP and 425 RA lacking CLD was conducted. Results LRRC37A2 rs199526C was significantly associated to EMP in RA according to an allele model (p = 0.0083, odds ratio [OR] 1.72, 95% confidence interval [CI] 1.14-2.59) or recessive model for major alleles (p = 0.0139, OR 1.82, 95% CI 1.13-2.94), although it was protectively associated against IPF in European populations. Multiple logistic regression analyses revealed an independent association with age, Steinbrocker stage, and Steinbrocker class. An association between LRRC37A2 rs199526 and RA per se was detected. Conclusion An association between rs199526 and EMP was noted in Japanese RA. Differential roles of the single nucleotide variant between EMP in RA and IPF were suggested.