TRIM21 and myositis disease: As a consequence of the association of anti-Ro-52 with anti-aats and other studies that link myositis-specific anti-Mi-2 and anti-signal recognition particle (SRP) to anti-Ro-52, [9] it was hypothesised that the three antibody groups described as having an increased incidence of muscle involvement (AFA, anti-Pm-Scl, anti-U1-RNP) might show an increased association of anti-Ro-52 compared to the major SSc-specific antibody groups (ACA, ATA, ARA) where myositis is not a prominent feature [12].