What is Gene Therapy?
Genes, which are carried on chromosomes, are the basic physical and functional units of heredity. Genes are specific sequences of bases that encode instructions on how to make proteins. Although genes get a lot of attention, it s the proteins that perform most life functions and even make up the majority of cellular structures. When genes are altered so that the encoded proteins are unable to carry out their normal functions, genetic disorders can result. Gene therapy is a technique for correcting defective genes responsible for disease development. Researchers may use one of several approaches for correcting faulty genes: • A normal gene may be inserted into a nonspecific location within the genome to replace a nonfunctional gene. This approach is most common. • An abnormal gene could be swapped for a normal gene through homologous recombination. • The abnormal gene could be repaired through selective reverse mutation, which returns the gene to its normal function.
Gene therapy is an experimental technique that uses genes to treat or prevent disease. In the future, this technique may allow doctors to treat a disorder by inserting a gene into a patient’s cells instead of using drugs or surgery. Researchers are testing several approaches to gene therapy, including: • Replacing a mutated gene that causes disease with a healthy copy of the gene. • Inactivating, or “knocking out,” a mutated gene that is functioning improperly. • Introducing a new gene into the body to help fight a disease. Although gene therapy is a promising treatment option for a number of diseases (including inherited disorders, some types of cancer, and certain viral infections), the technique remains risky and is still under study to make sure that it will be safe and effective. Gene therapy is currently only being tested for the treatment of diseases that have no other cures.
Advances in understanding and manipulating genes have set the stage for scientists to alter a person’s genetic material to fight or prevent disease. Gene therapy is an experimental treatment that involves introducing genetic material (DNA or RNA) into a person’s cells to fight disease. Gene therapy is being studied in clinical trials (research studies with people) for many different types of cancer and for other diseases. It is not currently available outside a clinical trial. • How is gene therapy being studied in the treatment of cancer? Researchers are studying several ways to treat cancer using gene therapy. Some approaches target healthy cells to enhance their ability to fight cancer. Other approaches target cancer cells, to destroy them or prevent their growth. Some gene therapy techniques under study are described below. • In one approach, researchers replace missing or altered genes with healthy genes. Because some missing or altered genes (e.g.
Some human diseases are caused by a defective gene. An example is cystic fibrosis, a disease of mucous glands throughout the body that usually develops during childhood and makes breathing increasingly difficult. If a child receives two copies of the defective gene called the CF gene — one copy from each parent — then the child will develop the disease. Biotechnology is used in several ways in detecting, diagnosing and treating cystic fibrosis.
