Jüschke et al. showed that engineered U1 splice factors targeted to intron 10 can ameliorate the effect of c.1065+5G>A variant, which causes exon 10 skipping, and this proof-of-concept study indicates the feasibility of splice-site variant correction as a therapeutic option for OPA1-related mitochondrial diseases [99]. This evidence concerns the gene OPA1 and inborn mitochondrial metabolism disorder.