The anti-MDA5 subgroup of JDM versus the rest of JDM was characterized by increased cutaneous ulceration (7/10, 70% vs. 8/46, 17%) and interstitial lung disease (ILD) (7/10, 70% vs. 1/46, 2%) with less weakness defined as a MMT score of < 225/260 (0/8, 0.0% vs. 8/28, 29%). Here, IFIH1 is linked to interstitial lung disease.