In mucopolysaccharidosis type I (MPSI), integration of the iduronidase (IDUA) gene into the CCR5 locus of human CD34+ hematopoietic stem cells (HSCs) led to high levels of the IDUA enzyme secretion, maintained capacity to differentiate into multiple blood cell lineages, and improved both biochemical and phenotypic abnormalities in an immunocompromised MPSI mouse model [177]. This evidence concerns the gene CD34 and mucopolysaccharidosis type 1.