Patients were categorized into clinically and serologically defined subgroups: DM (n=82, including anti-Mi2 [n=22], anti-NXP2 [n=21], anti-TIF1γ [n=28], and anti-MDA5 [n=11]), ASyS with anti-Jo1 antibodies (n=37), IMNM (n=80, including anti-HMGCR [n=60] and anti-SRP [n=20]), and IBM (n=53) (Supplementary Table 1). This evidence concerns the gene MORC3 and inclusion body myositis.