Gene therapy is an exciting treatment option that is starting to take off in the field of treating genetic diseases. Three women in the United States, who had previously been treated for genetic blindness with gene therapy in one eye, have been treated in the second eye, and the results are looking promising (http://www.bbc.co.uk/news/health-16942795). Gene therapy is still only in its early stages as a treatment option, but the promise of recent studies into its success in treating genetic eye diseases mean this technology is on the rise and could soon become a widespread treatment option throughout the world.
Genetic disorders are caused by the malfunctioning of one or more of our genes, which prevent the proteins in our body, which are instructed by the genes, from fulfilling their normal functions (http://www.ornl.gov/sci/techresources/Human_Genome/medicine/genetherapy.shtml). In gene therapy, the malfunctioning gene is replaced by a new, better-functioning gene, which is inserted into the area of the body where the faulty gene is located (http://www.scientificamerican.com/article.cfm?id=experts-gene-therapy). If we do not replace this malfunctioning gene, it can be the cause of disease within in the body. Gene therapy was first tested for treating genetic blindness back in 2008, when a research team at Moorfields Eye Hospital’s NIHR Biomedical Research Centre in the UK used gene therapy successfully on the eyes of human patients, proving it was safe and helped to improve their sight (http://www.ornl.gov/sci/techresources/Human_Genome/medicine/genetherapy.shtml).
In early 2012, three women in the US were treated with a second round of gene therapy to relieve their genetic blindness, caused by an inherited condition known as Leber’s Congenital Amaurosis (LCA). LCA is a very rare disease, appearing just after birth, and occurring as cells from the retina, the “light-sensitive layer of cells at the back of the eye” (Briggs 2012), progressively die out over time, degrading the vision of the sufferer. It is caused by a faulty gene in the cells of the retina, RPE65, and gene therapy aims to fix this by injecting a virus containing a functioning version of the gene into the eye. Dr Jean Bennett, of the University of Pennsylvania’s Mahoney Institute of Neurological Sciences, first treated the three women with this method back in 2008. At the time, twelve people suffering from LCA were injected in just one eye, recovering some vision in the injected eye, and in early 2012, the three women were chosen out of the twelve to have the procedure repeated in the second eye, showing a notable improvement in the vision quality in both eyes. Information regarding Dr Bennett’s most recent results in this area can be found in the February 8th edition of Science Translational Medicine (http://stm.sciencemag.org/content/4/120/120ra15.full.html 2012).
It is evident that, in the last few years, gene therapy has started to emerge as a potentially successful treatment for genetic diseases, in particular those involving genetic blindness. Recent studies, such as the ones referred to above, have demonstrated gene therapy to be successful in improving vision quality for those suffering from inherited eye diseases, such as LCA, and have provided evidence that it is a safe treatment option. It is hoped that these discoveries will lead to more widespread use of gene therapy as a valid treatment for genetic blindness, and will improve the quality of life of those suffering from poor vision quality as a result of inherited eye conditions.