Although there were variations in the data from individual cell lines for each characterization (Fig. S1), we did not see an overall significant difference in the number of Pax7-positive cells (Fig. 1C), the fiber width (Fig. 1D) or the fusion index (Fig. 1E) when comparing the average of control and C9-ALS lines. This evidence concerns the gene PAX7 and amyotrophic lateral sclerosis.