SNRNP70 and polymyositis: Anti-U1RNP were identified in 14 (4%) of myositis patients and were associated with an older age at disease onset (OR 1.19 (1.04–1.36), p = 0.011) and polymyositis or polymyositis overlap (OR 45.4 (6.88–299.79), p < 0.001).