In those with juvenile-onset disease, where an association between anti-TIF1γ and malignancy is not seen, both autoantibodies have been shown to have a lower prevalence: anti-Sp4 autoantibodies were found in 20% of anti-TIF1γ positive juvenile IIM patients from the USA and were associated with Raynaud’s, milder muscle weakness and lower peak aspartate aminotransferase (AST) [11]. This evidence concerns the gene SP4 and acquired idiopathic inflammatory myopathy.