IFIH1 and clinically amyopathic dermatomyositis: The anti-melanoma differentiation-associated gene antibody (anti-MDA5) is a myositis-specific autoantibody (MSA) against a 140-kDa polypeptide described by Sato et al. in 8 Japanese patients with clinically amyopathic dermatomyositis (CADM) [2].