Table 1.

Demographic features of 64 patients with childhood idiopathic inflammatory myopathies. Of the 17 patients with myositis overlap syndromes, 3 had mixed connective tissue disease, 3 had systemic lupus erythematosus, and the remainder had myositis in overlap with other connective tissue diseases.

FeatureTotal, n = 64JDM, n = 40JPM, n = 7Myositis Overlap Syndromes, n = 17
Sex F/M48/1630/105/213/4
Mean age at onset, yrs8.38.79.810.8
Mean disease duration, yrs4.543.54.8
Mean followup, yrs3333.8
  • JDM: Juvenile dermatomyositis; JPM: Juvenile polymyositis.