The incidence of arthritis (55.9% vs. 27.3%, χ2 = 6.555, p = .019), fever (35.3% vs. 6.8%, χ2 = 10.013, p = .003), skin ulcer (32.4% vs. 4.5%, χ2 = 10.678, p = .002), Gottron's signs (91.2% vs. 38.6%, χ2 = 22.369, p = .001), and RP‐ILD (64.7% vs. 2.3%, χ2 = 39.65, p = .001) was significantly higher in patients with anti‐MDA5 Ab compared with patients without anti‐MDA5 Ab. Here, IFIH1 is linked to arthritic joint disease.