DM1 and DM2 patients suffer from cardiac damage including abnormalities of the conduction system (31) and myocardial fibrosis (32, 33); though left ventricular mass was reduced in more than 60% of DM patients, in agreement with previous reports (33), plasma irisin did not correlate with left ventricular mass in both DM1 and DM2 patients. The gene discussed is FNDC5; the disease is myotonic dystrophy type 1.