Another way to define gene therapy is the replacement of defective genes with genes which are healthy. Once the healthy genes combine with the DNA of the patient, the DNA will trigger new cells and target what they need to target. Among the diseases that are considered "treatable" by GT are cystic fibrosis and Parkinson’s disease, cancer, Huntington’s disease, retinal degeneration, types of blindness, phenylketonuria (PKU), AIDS, ageing and many more. GT has been applied with partial success in cases of blindness. Yet, as we have talked about it as a society, not once has a case of GT been successful enough to, for instance, cure Cancer, AIDS, or reverse aging. The FDA has not approved as of yet any product that is conducive to the application of GT, and not enough practice has been given to prove that it works. It is then a matter of time to decide whether it is worth investing time and money on it.
Gene therapy is a method for treating diseases in which the cells of a patient's body are provided with a normal gene to make up for a defective or missing gene. The technique either to correct a defect in a patient's cells or to instruct the cells to carry out a new function.
The technique of gene therapy is still in the early stages of development and is not used that commonly. But it offers hope for effective treatment in future of treating diseases such as sickle cell anaemia, AIDS, cystic fibrosis, and some forms of cancer, that are incurable today.
Gene therapy consists of three main steps:
(1) Removing some cells from the patient's body.
(2) Inserting a corrective gene from another individual or organism into these cells.
(3) Returning the altered cells to the body.
The altered cells are returned to the patient's body by means of a vector, which is the name given to any substance or piece of equipment capable of carrying therapeutic genes to the cells that need them.
Once altered cells are in the body of the patient, the new genes automatically begin to treat the disease. This 3 step process is repeated until the body maintains its own supply of the new gene through normal cell growth.
Gene therapy was first used in 1990 at the U.S. National Institutes of Health.
The use of gene therapy has evoked controversial responses from knowledgeable people. Some people fear that gene therapy may permanently alter the basic substance of human beings if genes from other species are used. In view of such possibilities, it is desirable for governments to monitor and control its use.