A completely curative process for someone suffering from ADA deficiency is

In some children, ADA deficiency can be cured by bone marrow transplantation; in others, it can be treated by enzyme replacement therapy, in which functional ADA is given to the patient by injection. But the problem with both of these approaches that they are not completely curative. Gene therapy is a collection of methods that allows correction of a gene defect that has been diagnosed in a child/embryo. However, if the gene isolate from marrow cells producing ADA is introduced into cells at early embryonic stages, it could be a permanent cure.