The genetic defect - Adenosine deaminase (ADA) deficiency may be cured permanently by:
administering adenosine deaminase activators.
Introducing bone marrow cells producing ADA into cells at early embryonic stages.
enzyme replacement therapy.
periodic infusion of genetically engineered lymphocytes having functional ADA cDNA.
By introducing bone marrow cells that produce ADA and assist in purine metabolism in embryonic cells, the genetic defect of adenosine deaminase deficiency can be corrected.
Hence, the correct answer is option 2).