KCNMA1 and myotonic dystrophy type 1: The treatment of normal myoblasts with paxilline decreased myotube fusion by 36% (Figures 5a and c) and mef2 expression by 18% (Figures 5d and e), thus showing that the loss of functional KCa1.1 channels is sufficient to induce a decrease in myoblast fusion, as seen in DM1.