F9 and hemophilia: In addition to the in vivo trials on cervical cancer, ZFN-mediated gene editing has been used to treat hemophilia.134–137 ZFN-based gene correction of factor IX, α-l-iduronidase, and iduronate-2 sulfatase have proceeded to clinical trials for hemophilia, mucopolysaccharidosis type I (MPS I), and MPS II, respectively.