Anti-melanoma differentiation-associated gene 5 antibody (anti- Melanoma Differentiation-Associated protein 5 (MDA5) antibody)-positive myositis complicated with interstitial lung disease (referred to as anti-MDA5 antibody-positive interstitial lung disease) is a rapidly progressive inflammatory lung disease subtype with a poor prognosis. This evidence concerns the gene IFIH1 and interstitial lung disease.