MSTN and dermatomyositis: Myostatin levels were lower in ASyS (3109 [1952; 4258] pg/ml; p = 0.001), DM (2327 [1431; 3446] pg/ml; p < 0.0001), IMNM (2285 [1371; 3851] pg/ml; p < 0.0001) and IBM (2005 [1449; 2803] pg/ml; p < 0.0001) compared to HD (4281 [3169; 5787] pg/ml) (Figure 1C).