Gene Therapy
Genes are the basic physical and functional units of heredity. Genes control heredity and provide the basic biological code for determining a cell's specific functions. Gene therapy is a rapidly growing field of medicine in which defective genes responsible for disease development are corrected during the treatment. The technology is still in its infancy.
Progress is being made, however. Gene therapy has been used to treat several children with severe combined immunodeficiency disorder (SCID), a rare and often deadly disease in which the immune system doesn't work properly. Gene therapy has restored the immune systems of more than a dozen children with this disorder. But there have also been some complications from this treatment: a few of the children have developed leukemia as a result of therapy. Such unforeseen problems have caused researchers to temper their enthusiasm and to be more cautious with further studies.
One of the following approaches may be used for correcting faulty genes:
- A normal gene is inserted into a nonspecific location within the genome to replace a nonfunctional gene. This is the most common approach.
- An abnormal gene is swapped for a normal gene through homologous recombination.
- The abnormal gene is repaired through selective reverse mutation in order to return it to its normal function.
- The regulation (the degree to which a gene is turned on or off) of a particular gene is altered.
Anna L. Kaplan, M.D.
