Today scientists are experimenting with gene therapy as a way to permanently help people who have hemophilia and other inherited diseases. Gene therapy involves inserting healthy genes into human cells to correct or prevent diseases. When genes are introduced into body cells other than eggs and sperm, this is called somatic cell gene therapy. Any effects are limited to the person receiving the therapy as the new genes are not passed on to future generations.
Germ line gene therapy refers to the correction of a genetic problem in an individual’s egg or sperm. This means that once a problem such as hemophilia is corrected inside the reproductive cells, it cannot be passed on to offspring. In addition hemophilia, gene therapy trials have been conducted on people with muscular dystrophy, cystic fibrosis, HIV infection, rheumatoid arthritis, acute hepatic failure, many forms of cancer, a rare enzyme disorder called
ADA deficiency, and other diseases.
Scientists are hopeful that gene therapy, if we can perfect it, can become a useful weapon against some of the terrible diseases just mentioned and malformations. At present, gene therapy is still in the early stages of development, and, as is typical of any therapy, it does not always work as planned. Scientists can put new DNA into cells they want to improve, but inserting the
DNA so it reaches the right destination is a major problem. Sometimes diseased or dysfunctional cells are removed from the patient, and healthy DNA is injected into them. The “corrected” cells are grown in large numbers, then injected back into the patient. Another method of getting new
DNA into a patient’s cell is to use a carrier.
Carriers are usually viruses that have been rendered harmless. The virus cells are injected with the DNA intended to help the patient. The viruses are also given the capacity to recognize target cells. When the modified virus