Moreover, upon co-culture of CRISPR/nCas9-modified CD34+ cells with human MPS IVA fibroblasts, a significant increase in GALNS activity was observed in MPS IVA fibroblasts, suggesting that human CD34+ cells-derived GALNS enzyme was successfully uptaken by human MPS IVA fibroblasts. Here, CD34 is linked to mucopolysaccharidosis type 4A.