Gene therapy is a medical technique that manipulates genes to treat or prevent a disease. Gene therapy research is focused on the following approaches:
· Replacing a gene responsible for disease with a healthy gene.
· Inactivating or ‘knocking out’ a gene that is functioning improperly.
· Introducing a new gene into the body to help fight a disease.
In future, this technique may allow doctors to treat a disorder by manipulating a gene into a patient’s cells instead of using drugs or surgery. Gene therapy is a treatment option for a number of diseases (including inherited disorders, some types of cancer and certain viral infections).
Use of Vector to Introduce a Gene
Usually, a gene that is inserted directly into a cell does not function on its own. Instead, a carrier called a vector is genetically engineered to deliver the gene. Certain viruses such as retrovirus are often used as vectors, because they can deliver the new gene by infecting the cell. The viruses are modified so that they cannot cause disease when inserted into people.
The vector can be injected, or given intravenously (by IV), directly into a specific tissue in the body, where it is taken up by individual cells.
Alternately, a sample of the patient’s cells can be removed and exposed to the vector in a laboratory setting. The cells containing the vector are then returned to the patient. If the treatment is successful, the new gene delivered by the vector will make a functioning protein.
Concerns over Gene Therapy
1. Short-lived nature of treatment:
Before gene therapy can become a permanent cure for a condition, the therapeutic DNA introduced into the target cells must remain functional and the cells containing the therapeutic DNA must be stable.
Problems with integrating thera- peutic DNA into the genome and the rapidly dividing nature of many cells prevent it from achieving long-term benefits. Patients undergoing gene therapy often require multiple treatments.
2. Immune response: Depending upon the number of times a foreign object is introduced into our body; the immune system is stimulated to attack the invader. As a result, the gene therapy might activate the response of our immune system. Even our immune system reduces the effectiveness of gene therapy.
3. Multi-gene disorders: Some commonly occurring disorders such as heart disease, high blood pressure, Alzheimer’s disease, arthritis and diabetes are affected by variations in multiple genes, which complicate the use of gene therapy.
Presently, the technique remains risky. It is not yet proven to be safe and effective. Gene therapy is currently being tested only for the treatment of diseases that have no other cures.