COL6A1 and hydrops fetalis: The allele-specific analysis was performed with the CRISPResso2 webtool and showed a 32.31% efficiency of editing the mutated allele and a 2.37% editing of the WT allele, confirming the HF Alt-R SpCas9/gRNA3 complex as the most specific and efficient for the c.824_838del pathogenic variant of COL6A1 (Figure 2A and Figure S1).