To clarify the differences in the clinical features and prognosis between anti-MDA-5 antibody-positive and -negative cases, we retrospectively reviewed the medical records of patients diagnosed with CADM-ILD with and without anti-MDA-5 antibody at Kurashiki Central Hospital from January 2005 to September 2014. This evidence concerns the gene IFIH1 and clinically amyopathic dermatomyositis.