The field of gene therapy is much misunderstood. Though still in its formative stages, some key successes have already been achieved, proving the effectiveness of gene therapy in treating a range of diseases.
We take a look at this experimental technique, its applications in modern day medicine, and the ways in which gene therapy has already proved an effective treatment in targeting genetic disease.
How does gene therapy work?
Gene therapy affects disease on a cellular level rather than merely treating the symptoms. Its gradual implementation in modern day healthcare marks a shift away from generic treatments to personalized medicine.
Scientists attribute the cause of many diseases to gene abnormalities. These abnormalities can prevent cells acting in the way that they should, interrupting important processes such as protein and enzyme production. This impacts the body’s ability to function efficiently and ultimately compromises human health.
Gene therapy allows scientists to attack the root cause of disease in a number of ways. These include introducing a new gene to “teach” the body to fight disease; inactivating a gene that is not functioning properly; and replacing mutated genes with healthy gene copies.
Although gene therapy shows promise in treating a range of diseases, the technique is still regarded as high-risk. Because of this, doctors are reserving this form of treatment for only the most serious cases in diseases with no known cure. Much research remains outstanding in terms of proving gene therapy’s safety and effectiveness before it can be fully incorporated into mainstream medicine, though results gathered from several studies have been very encouraging.
When was gene therapy first used to treat humans?
The procedure was first used in 1990 by Dr W. French Anderson at the NIH Clinical Center. Anderson was treating a 4-year-old girl who had an adenosine deaminase deficiency. It wiped out her immune system and left her vulnerable to infection.
Anderson extracted white blood cells from the girl, adding to them healthy genes capable of synthesizing adenosine deaminase. He then reintroduced the white blood cells to the girl’s body in this landmark clinical trial.
She went on to lead a normal life, the treatment ultimately proving highly successful. Gene therapy has since been administered to newborns showing signs of adenosine deaminase disease. These individuals have shown increased immunity after just one course of treatment.
What diseases can specialists target with gene therapy?
Scientists believe gene therapy shows a great deal of promise in the treatment of a wide range of genetic diseases. Diseases that could one day be treated may include hemophilia, congenital blindness, muscular dystrophy, chronic granulomatous disease, various forms of cancer, Parkinson’s disease, and Huntington’s disease.
Scientists also believe the procedure could prove beneficial in the treatment of a number of acquired illnesses. Possibilities include influenza, HIV, hepatitis, heart disease, and diabetes.
Gene therapy in sickle cell disease
This blood disorder is caused by a gene mutation. Sickle cell disease causes a person’s red blood cells to form in a characteristic sickle-shape. This shape does not flow through the circulatory system as effectively as normal, oval-shaped red blood cells do. These sickle-shaped cells can get stuck in blood cells, causing painful blockages, affecting the body’s ability to deliver life-giving oxygen, and ultimately damaging tissue and organs.
Every year, approximately 275,000 babies are born with sickle cell disease worldwide. An estimated 90,000 US citizens have sickle cell disease.
A boy with sickle cell disease took part in clinical trials at the Nicker Children’s Hospital, Paris, in 2014. Specialists administered gene therapy to the 13-year-old. Within 38 days, his production of red blood cells had normalized, with no serious adverse reactions reported. The study paved the way for clinical gene therapy trials in the treatment of other blood disorders, such as thalassemia.
Gene therapy in cancer
Scientists have reported promising results from several cancer gene therapy trials. One study utilizes a specially adapted version of herpes simplex 1. This is the virus responsible for the common cold sore.
In laboratory conditions, scientists have managed to genetically manipulate the herpes simplex 1 to attack melanoma cells. This treatment, called T-VEC, has been modified so that it only kills cancer cells; does not cause cold sores; and triggers the patient’s own immune system to recognize and attack cancer cells.
Gene therapy in hereditary blindness
Several different gene therapies are currently being trialed to treat the different types of hereditary blindness, particularly in degenerative forms of the disease. Experiments have produced encouraging results, showing the potential of gene therapy to slow and even reverse vision loss.
In a trial of patients with Leber congenital amaurosis, a degenerative eye disease, gene therapy improved the vision of some candidates for several years. Though treatment failed to halt retinal degeneration completely, it did at least slow deterioration in vision.
The future of gene therapy
Though the technique is very much in its formative stages, the potential of gene therapy in curing disease is vast. With numerous clinical trials underway worldwide, the role of gene therapy in modern medicine is only expected to grow, marking a shift away from the traditional, one-size-fits-all approach, to one of personalized healthcare.