It was recently reported that CUGBP1 protein is overexpressed in muscle biopsies from patients affected by the adult classical form of DM1 but not in muscle from DM2 patients, suggesting that CUGBP1 overexpression in DM1 might be an additional pathogenic mechanism not shared by DM267. The gene discussed is CELF1; the disease is myotonic dystrophy type 1.