Brain and visceral gene editing of mucopolysaccharidosis I mice by nasal delivery of the CRISPR/Cas9 system.

Background: Mucopolysaccharidosis type I (MPS I) is an inherited disease caused by deficiency of the enzyme alpha-l-iduronidase (IDUA). MPS I affects several tissues, including the brain, leading to cognitive impairment in the severe form of the disease. Currently available treatments do not reach the brain.