This study also revealed a significant increase in mitochondrial mass and a pro-apoptotic profile in untreated MPS IVA fibroblasts, which was efficiently restored to WT levels upon co-culture with CRISPR/nCas9-modified CD34+ cells [73], paving the way for a novel ex vivo CRISPR/nCas9-based GT. Here, CD34 is linked to mucopolysaccharidosis type 4A.