Anti-melanoma differentiation-associated gene 5 antibody positive dermatomyositis (MDA5+ DM), a subtype of idiopathic inflammatory myopathies (IIMs), is distinguished by a high risk of rapidly progressive interstitial lung disease (RP-ILD), scarcely clinical evidence of myopathy, and typical skin lesions. The gene discussed is IFIH1; the disease is retinitis pigmentosa 1.