There are three techniques that researchers are working on. The defective cells are removed from the patient and replaced with the normal DNA before returning to the body. This therapy targets the blood cells because many genetic defects alter the functioning of one type of these cells or another. But since blood cells have limited life spans follow-up treatments are required. Future efforts will most likely target stem cells of the bone marrow.
Stem cells are ideal for gene therapy because they appear to be immortal.
Cells carrying corrective genes are introduced directly into the tissue where the genes are needed. This treatment is good for conditions that are localized, but it cannot correct systemic disorders. In situ treatment is being explored for diseases like cystic fibrosis, muscular dystrophy, and cancer. This therapy does not exist yet but is the therapy of the future. Researchers hope to inject gene carriers into the bloodstream.