APOA4 and myopathy: For example, calcium/calmodulin‐dependent protein kinase type 1 G (CAMK1G), early growth response protein 4 (EGR4), and CXC motif chemokine ligand 8 (CXCL8), also known as interleukin 8 (IL‐8), were highly expressed in ankylosing spondylitis (AS) but not in DM or other types of myositis, while apolipoprotein A4 (APOA4) was only expressed in anti‐3‐hydroxy‐3‐methylglutaryl‐CoA reductase (HMGCR) myopathy, and mucosal vascular addressin cell adhesion molecule 1 (MADCAM1) was exclusively expressed in anti‐Mi2‐positive DM.38