In the 60 years since Watson and Crick’s landmark discovery of the structure of DNA, our understanding of how genes influence disease has increased exponentially. For some conditions, an exciting therapeutic prospect exists: gene therapy. Gene therapy attempts to repair faulty genes instead of simply treating symptoms.
For many conditions, the exact genetic mechanisms underlying them have now been elucidated. While a lot of diseases are the result of a complex interaction between multiple genes and environmental factors, others are the result of a single mutation, resulting in the failure to produce an essential functional protein. For such conditions, an exciting therapeutic prospect exists: gene therapy. In principle, the idea behind gene therapy is very simple. Whereas conventional medicine generally attempts to replace the missing gene product or repair the damage caused by its absence, gene therapy attempts to repair the faulty gene itself. Why treat symptoms when you can treat the cause?
Since its conceptualisation in 1974, gene therapy has come a long way, and we are now tantalisingly close to having gene-based treatments for many debilitating congenital diseases such as haemophilia, cardiovascular disease, adrenoleukodystrophy, severe combined immunodeficiency and muscular dystrophy, to name a few. Over 1700 clinical trials have now been conducted using a variety of different gene therapy techniques. The potential benefits of gene therapy over more traditional therapies are the replacement of a lifetime of medication with just a single treatment, and the eradication of side effects, not to mention the relief of the huge financial burden of lifetime treatment. But to date, only a single gene therapy treatment has been approved for use in humans. Why the delay? Well, although conceptually simple, the application of gene therapy remains one of the biggest technical challenges faced by modern medicine.