The AAV-CRISPR system is particularly useful for editing disease-associated genes in the brain or central nervous system of mice due to the inability of most cationic nanocarriers to cross the blood-brain barrier, high transduction efficiency of AAV vectors in the brain, and non-dividing properties of neurons for long-term therapeutic effects. The AAV-CRISPR system has also been successfully used to restore the gene function in muscle-associated diseases such as Duchenne muscular dystrophy and diseases associated with the liver, heart, eye, and lung.