DMD and myotonic dystrophy type 1: Next we analyzed alternative splicing patterns in urine exRNA of DM1, UA controls, and 15 individuals with mutations in the dystrophin (DMD, in italics) gene as muscular dystrophy controls (N = 12 Duchenne muscular dystrophy [DMD, no italics], 3 non-ambulatory Becker muscular dystrophy [BMD]; Supplementary Tables 3, 4), focusing on transcripts previously reported as biomarkers of DM1 disease severity in muscle biopsies (Supplementary Table 5)4.