The final diagnoses for the 6 patients with strongly positive MSAs deemed to be false positives included immune checkpoint inhibitor related myofasciitis (n = 1; anti-EJ), genetic myopathy (n = 1; anti-Mi2B with anti-PL7), fibromyalgia (n = 1; anti-Jo1), and unclear final diagnoses (n = 3; anti-Mi2B, anti-TIF1γ, and anti-EJ). This evidence concerns the gene CHD4 and fibromyalgia.