A patient is suffering from ADA deficiency. Can he be cured? How?

ADA (i.e., adenosine deaminase) deficiency is a genetic disorder caused by the deletion of a gene for adenosine deaminase synthesis which leads to the deficiency of the ADA enzyme in the body which causes damage to the immune system. It can be cured by various approaches like:

i) A bone marrow transplant can cure the disease. Suitable bone marrow is required for the transplant.

ii) Enzyme replacement therapy can be used. The adenosine deaminase enzyme can be injected in the body.

Both of these approaches help in curing ADA but they do not completely cure the ADA deficiency disease.

Another approach of gene therapy has been found to be highly successful. It involves growing lymphocytes outside the body of the patient in a cell culture and using a functional ADA complementary DNA (i.e., cDNA) in those lymphocytes. This treatment is recurrent in nature because these ADA cDNA are not immortal and new cells need to be injected timely to the patient however if this procedure can be carried at an early embryonic stage in the bone marrow then gene therapy can be a permanent cure.