Fig. 3.

The median age at disease onset for patients with juvenile-onset myositis was 6.9 years. As illustrated, the median age at disease onset varied between autoantibody subgroups. Anti-U1RNP, anti-synthetase and ‘other’ myositis associated autoantibodies were all more likely to be identified in older patients. ASS; anti-synthetase (3 patients with anti-Jo-1, 2 anti-PL12 and 1 anti-PL7) other; 1 anti-Ku, 1 anti-SCl70, 1 anti-Ro60, 1 anti-U3RNP, 1 anti-Mitochondrial antibody. None identified; No known autoantibody identified using the techniques described (42% of this group have unidentified bands visible on immunoprecipitation).