Gene therapy – the future of treatments for macular disease?

Posted: Tuesday 19 February 2019

Gene therapy is a medical technique that may sound like it’s from the pages of science fiction, but it is moving closer and closer to becoming a part of medicine. Treatments for eye diseases seems to be an area that gene therapy is progressing in with success, and has a lot of potential to provide treatments, including for people with macular disease.

What is gene therapy, and how does it work?

We all inherit two copies of each of our genes – one from our mother, and one from our father. For every gene, across the human population there will be lots of different varieties, as a result of random changes throughout evolution. Many of these changes won’t have any effect, and won’t be noticed. Some produce differences that aren’t harmful – for example, different coloured eyes or hair. But some varieties may cause problems, either if you have two copies that don’t work properly, or sometimes just one.

Many juvenile macular dystrophies are caused by “faults” in the varieties of the genes that are inherited. Genes play a role in the development of age-related macular degeneration (AMD), although the faults don’t cause problems as early in life.

Each gene will have a specific job to do. Sometimes, faults in genes will mean that the gene doesn’t behave in the right way and do the job that it should. Depending on what job this is and how important it is, it can lead to problems.

Gene therapy aims to replace faulty variations of genes with versions without the faults, with the hope that they will then start to perform their job correctly. The technique most commonly used for editing genes is called CRISPR (pronounced crisp-er). The Macular Society funds research studies that use this technique to understand macular diseases and work towards a cure.

Gene therapy as a treatment for eye health

A recent trial has seen success using gene therapies in another eye condition called Leber’s congenital amaurosis. Although not related to macular disease, the success of gene therapy within the eye shows great promise. In this case, gene therapy has resulted in great improvements in participants’ vision.

Other companies are now embarking on the development of gene therapies for macular diseases.

One of the things that stands in the way of future gene therapies is that you need to know which gene is causing a problem. This isn’t always clear, which is why we need to fund more research to investigate what causes different macular diseases.

We will keep you informed of progress in this area as it happens, especially studies that are investigating gene therapy as a treatment for macular diseases, such as the recent trial at Oxford Eye Hospital.