It depends on when the gene normally expresses. Some genetic disorders result in incorrect development of organs, which means that gene therapy alone will never

It depends on when the gene normally expresses. Some genetic disorders result in incorrect development of organs, which means that gene therapy alone will never resolve the issue. Organ donation or surgery plus gene therapy might be a possible cure for some such disorders, though. But if a condition just results in producing too much of a hormone or something like that it could be addressed with just gene therapy.