Age at diagnosis in years, median (IQR) | 8 (4.0–11.5) |
Age at disease onset in years, median (IQR) | 7 (3.5–7.5) |
Time to diagnosis in months, median (IQR) | 3 (1–6.5) |
Female, N (%) | 76 (63.4) |
Race or Ethnicitya, N (%) | |
White | 86 (72.3) |
Hispanic, Latino, or Spanish origin | 22 (18.5) |
Black, African American, African, or Afro-Caribbean | 9(7.6) |
Asian | 7(5.9) |
Native American, American Indian or Alaskan Native | 3 (2.5) |
Middle Eastern | 3 (2.5) |
Unknownb | 3 (2.5) |
Otherc | 4 (3.4) |
Concomitant Medical History, N (%)d | 22 (16.8) |
Family History of Autoimmunity, N (%)e | 25 (21) |
Skin Predominant JDM, N (%) | 38 (31.9) |
History of, N (%) | |
Proximal Muscle Weakness | 86 (72.3) |
Rash (Heliotrope or Gottron’s) | 110 (92.4) |
Elevated muscle enzymes | 99 (83.2) |
EMG performed | 4 (3.4) |
Muscle Biopsy performed | 19 (16) |
MRI performed | 81 (68.1) |
Autoantibodies, proportionf | |
ANA | 75/96 (78.1%) |
Myositis-specific antibodies | |
Anti-MJ/NXP2 | 11/49 (22.4%) |
Anti-p155/140/TIF1-𝛄 | 7/53 (13.2%) |
Anti-Mi2 | 6/55 (10.9%) |
Anti-MDA5 | 4/51 (7.8%) |
Anti-Jo1 | 2/67 (3.0%) |
Myositis-associated antibodies | |
Anti-PM-Scl | 3/43 (7.0%) |
Anti-Smith | 1/56 (1.7%) |