The ddPCR analysis with probes designed to distinguish mutant and WT COL6A1 transcripts showed a significantly lower ratio between the mutant transcript over the WT one, compared to the control UCMD fibroblasts (ratio: RNP ctr = 0.96, RNP-gRNA3 = 0.58, p = 0.0136, Figure 3A), calculated in five independent experiments. This evidence concerns the gene COL6A1 and Ullrich congenital muscular dystrophy.