Gene therapy is a collection of methods that allows correction of a gene defect that has been diagnosed in a child / embryo.
Correction of a genetic defect involves delivery of a normal gene into the individual or embryo to take over the function of and compensate for the non-functional gene.
The first clinical gene therapy was given in 1990 to a 4-year old girl with adenosine deaminase (ADA) deficiency caused due to the deletion of the gene for adenosine deaminase , an enzyme important for the immune system to function.
Cure – 1.Bone marrow transplantation
- Enzyme replacement therapy,
3.Gene therapy – lymphocytes from the blood of the patient are grown in a culture in-vitro. A functional ADA – cDNA (using a retroviral vector) is then introduced into these lymphocytes, & reintroduced to the patient. As cells are not immortal, the patient requires periodic infusion of such genetically engineered lymphocytes.
- Gene for ADA, isolated from marrow cells are introduced into cells of patient at early embryonic stages, could be a permanent cure.