D-F As previously described in patient's primary myoblasts, patient-LV-GFPmyoblasts showed a striking facilitated differentiation compared to control-LV-GFP-myoblasts. This phenotype fully disappeared in patient-LV-GFP-NICD myoblasts, as quantification of the fusion index (E), and myogenin expression (F) demonstrated. The data support a pathogenic role for Notch inhibition on the altered differentiation in our patients. Data were collected from n = 3 independent assays (13-17 images per condition). Mean ± SEM is shown; Kruskal-Wallis with Dunn´s multiple comparisons test; Scale bar, 50 µm). 