JAK2 and antisynthetase syndrome: Next, we searched PubMed for studies on JAK2 V617F mutation with adult IIM using the keywords “JAK2 V617F” and “idiopathic inflammatory myopathy”(IIM) or “dermatomyositis” or “polymyositis(PM)” or “antisynthetase syndrome(ASS)” or “immune-mediated necrotizing myopathy” or “inclusion body myositis” in English from 2000 to 2024.