Muscle and skin biopsies were not performed due to a probability of over 90% of DM based on the International Myositis Classification Criteria Project (IMCCP) (age > 50 years: 2.1; characteristic rash and mechanic's hand: 2.1; Anti-TIF-1γ Ab positive, as well as elevated aspartate aminotransferase and lactate dehydrogenase: 5.2; overall score: 9.4 > 7.5, corresponding to a probability of 90%) [13]. The gene discussed is TRIM33; the disease is dermatomyositis.