Abstract: A method for in utero genome editing, the method comprising administering to a subject an adenoviral vector, wherein the subject is a fetus, the adenoviral vector comprising CRISPR-mediated base editor and a guide RNA (gRNA), the gRNA targeting a mutation in a therapeutic gene; and introducing a modified codon in the therapeutic gene by base editing the therapeutic gene, wherein the base editing is performed by the adenoviral vector, an adeno-associated viral vector or lipid based nanoparticle.