Maybe. In the future gene therapy may be the way we treat scid, but right now the details of how to do this safely have not been proven. At the present time, bone marrow transplant is the mainstream of treatment. Trials may once again start with gene therapy at a few centers in the near future to see if this can be done safely.
Yes, experimental. Over 30 patients with severe combined immunodeficiency (scid) have been treated with gene therapy. They have included Adenosine deaminase deficiency form and the x-linked form. Results have been highly promising and favorable compared to bone marrow transplantation. Long-term benefits and side effects are still been studied.