Assessment of an additional list of 13 targets showed that both SaCas9-HF and WT SaCas9 displayed no or minimal off-target events on seven sites while in the other six sites SaCas9-HF significantly exhibited reduced off-target activities (mean off-target site number 3.0 for SaCas9-HF vs. 9.8 for WT SaCas9, one-sided Mann–Whitney U test p-value = 0.039) [22]. The gene discussed is CFH; the disease is hydrops fetalis.