DMPK and myotonic dystrophy type 1: ,39 To assess the potential impact of circARHGAP10 on DMPK transcriptional regulation, DM1-myogenic cells were transfected with siRNAs targeting circARHGAP10 or the linear transcript, and DMPK expression was evaluated at different time points in proliferating as well as differentiated myogenic cells (Figures 4A and S7A).