Association of a FAM13A variant with interstitial lung disease in Japanese rheumatoid arthritis.

Interstitial lung disease (ILD) occasionally occurs in rheumatoid arthritis (RA) and confers a dismal prognosis. We previously reported that a single-nucleotide variant (SNV) of MUC5B was associated with ILD in RA. However, the pathogenesis of ILD in Japanese patients with RA could not be explained solely by this SNV because its frequency is extremely low in the Japanese population. Here, we examined whether a different idiopathic pulmonary fibrosis susceptibility SNV might be associated with ILD in Japanese patients with RA. Genotyping of rs2609255 (G/T) in FAM13A was conducted in 208 patients with RA with ILD and 420 without chronic lung disease using TaqMan assays. A significant association with usual interstitial pneumonia (UIP) in RA was detected for rs2609255 under the allele model (p=0.0092, Pc=0.0276, OR 1.53, 95% CI 1.12 to 2.11) and recessive model for the G allele (p=0.0003, Pc=0.0009, OR 2.63, 95% CI 1.59 to 4.32). FAM13A rs2609255 was significantly associated with UIP in male patients with RA (p=0.0043, OR 3.65, 95% CI 1.52 to 8.73) under the recessive model. This study is the first to document an association of rs2609255 with ILD in Japanese patients with RA, implicating it in the pathogenesis of UIP, though studies on the function of rs2609255 are warranted.

Higuchi T ，Oka S ，Furukawa H ，Shimada K ，Tsunoda S ，Ito S ，Okamoto A ，Katayama M ，Saisho K ，Shinohara S ，Matsui T ，Migita K ，Nagaoka S ，Tohma S ... -  《-》

Association of family sequence similarity gene 13A gene polymorphism and interstitial lung disease susceptibility: A systematic review and meta-analysis.

Hu Y ，Li Z ，Ren Y ，Dai H ... -  《Molecular Genetics & Genomic Medicine》

MUC5B promoter variant rs35705950, rare but significant susceptibility locus in rheumatoid arthritis-interstitial lung disease with usual interstitial pneumonia in Asian populations.

MUC5B variant rs35705950 is the common and most significant risk variant for rheumatoid arthritis-interstitial lung disease (RA-ILD) in Western populations. However, little is known about its significant association with RA-ILD in Asian populations. We here investigate the association of rs35705950 with Korean patients with RA-ILD. In this cross-sectional study, we genotyped rs35705950 in 2444 patients with RA. Among them, 683 patients with RA who have chest CT were divided into RA-ILD and RA-noILD. RA-ILD was classified as usual interstitial pneumonia (UIP) and other than UIP. The associations of rs35705950 with RA-ILD and its subtype were analysed using multivariable regression adjusted for age at RA diagnosis. Meta-analysis of a previously reported Japanese dataset and Korean dataset obtained for this study was conducted. The minor allele (T) frequency of rs35705950 was 0.37%, 1.43% and 2.38% in 2444 patients with RA, 105 patients with RA-ILD and 63 patients with UIP, respectively. Genotypic association of rs35705950 with RA-ILD was insignificant (OR 2.49, 95% CI 0.64 to 9.69, p=0.187), but showed significant association with UIP (OR 4.90, 95% CI 1.23 to 19.59, p=0.024) compared with RA-noILD. In meta-analysis (123 UIP and 878 RA-noILD) combining our data with previously reported Japanese data, this variant was found to be significantly associated with UIP (OR 3.51, 95% CI 1.19 to 10.37, p=0.023). MUC5B variant rs35705950 is a rare but significant risk factor for Asian patients with RA-ILD with UIP, suggesting a sharing of the genetic background between Asian and Western populations.

Joo YB ，Ahn SM ，Bang SY ，Park Y ，Hong SJ ，Lee Y ，Cho SK ，Choi CB ，Sung YK ，Kim TH ，Jun JB ，Yoo DH ，Bae SC ，Lee HS ... -  《-》

Association of rare single nucleotide variant MUC5B rs35705950 with interstitial lung disease in Japanese rheumatoid arthritis.

Rheumatoid arthritis (RA) is sometimes complicated by interstitial lung disease (ILD) with a poor prognosis. A single nucleotide variant (SNV) in MUC5B was associated with ILD in European RA patients. However, associations of this SNV were not found in Japanese RA patients, because its frequency in Japanese populations is very low. We investigated the associations of candidate SNVs including the MUC5B variant with ILD in Japanese RA. Genotyping of MUC5B rs35705950, MUC2 rs7934606, MAD1L1 rs12699415, and PPFIBP2 rs6578890 in Japanese RA patients was conducted for association analyses. MUC5B rs35705950 was associated with usual interstitial pneumonia (UIP) (p = 0.0039, Pc = 0.0156, odds ratio [OR] 10.66, 95% confidence interval [CI] 2.05-55.37) or ILD (p = 0.0071, Pc = 0.0284, OR 7.33, 95%CI 1.52-35.44) in Japanese RA under the allele model. MUC2 rs7934606 was associated with UIP (p = 0.0072, Pc = 0.0288, OR 29.55, 95%CI 1.52-574.57) or ILD (p = 0.0037, Pc = 0.0148, OR 22.95, 95%CI 1.27-416.13) in RA. Haplotype analyses suggested the primary association of MUC5B rs35705950 with UIP in Japanese RA. No significant association of MAD1L1 rs12699415 or PPFIBP2 rs6578890 with UIP, nonspecific interstitial pneumonia, or ILD in RA was observed. MUC5B rs35705950 is associated with, and might be involved in the pathogenesis of ILD, especially UIP, in Japanese RA.

Higuchi T ，Oka S ，Shimada K ，Tsunoda S ，Ito S ，Okamoto A ，Fujimori M ，Nakamura T ，Katayama M ，Suzuki M ，Saisho K ，Shinohara S ，Matsui T ，Migita K ，Nagaoka S ，Tohma S ，Furukawa H ... -  《-》

FAM13A polymorphism is associated with a usual interstitial pneumonia pattern in patients with systemic sclerosis-associated interstitial lung disease.

The MUC5B promoter single nucleotide polymorphism (SNP) rs35705950 has been associated with idiopathic pulmonary fibrosis (IPF) and rheumatoid arthritis (RA)-related interstitial lung disease (ILD), but not with systemic sclerosis (SSc)-ILD. We hypothesized that the MUC5B promoter polymorphism or other IPF susceptibility loci are associated with an increased risk for the uncommon SSc-usual interstitial pneumonia (UIP) endophenotype, rather than SSc-ILD in general. We performed a cross-sectional study of SSc-ILD patients from 4 US Scleroderma Programs to investigate the frequency of MUC5B rs35705950 and 12 additional IPF susceptibility loci. SSc-ILD patients were stratified by high resolution chest CT (HRCT) imaging findings into UIP and non-UIP groups. Analysis of HRCTs performed by a thoracic radiologist blinded to participants' characteristics classified each scan as definite UIP, probable UIP, indeterminate, or alternative diagnosis, according to American Thoracic Society criteria. Four-hundred eighty-nine SSc-ILD patients were included; 80% were female and 75% were White. Twenty-three (4.7%) patients had a definite UIP pattern. The MUC5B SNP rs35705950 was not associated with a definite UIP pattern in SSc-ILD. In contrast, patients carrying 2 copies of the IPF risk gene FAM13A minor allele rs2609255 had significantly higher odds of a definite UIP pattern compared with the other patterns (OR 3.40, 95% CI 1.19-9.70), and compared with an alternative diagnosis (OR 3.65, 95% CI 1.25-10.65). We demonstrated a novel association between FAM13A and SSc-UIP. Contrary to IPF and RA-ILD, the MUC5B promoter polymorphism was not associated with a definite UIP pattern in SSc-ILD.

Bernstein EJ ，Boin F ，Elicker B ，Luo Y ，Ren Y ，Zhang M ，Varga J ，Assassi S ... -  《-》