Macular degeneration is thought of as a condition that affects people as they get older. However Stargardt's disease is a hereditary form of macular dystrophy which causes loss of sight at a much younger age.
There is currently no cure but with DNA screening underway in a gene therapy trial, a faint flicker of hope is emerging for people who suffer from this condition.
What is Stargardt's dystrophy?
People with Stargardt's experience a loss of central vision starting from anything between the ages of five and 20. Usually this means that they cannot read normal text, struggle to recognise faces, and will never be able to legally drive a car. The loss of sight is permanent, and at present there is no proven treatment to prevent or cure the disease.
Gene therapy and stem cell research
In 1997 a breakthrough study identified mutations in the ABCA4 gene as the cause of Stargardt's disease. The mutations slow the delivery of a protein involved in the transport of energy to photoreceptor cells which then causes a build-up of lipofuscin in the retinal pigment epithelium (the "nurse" layer of cells underneath the photoreceptors). This inhibits its ability to nourish photoreceptor cells and so they degrade, resulting in the loss of central vision. Researchers therefore believe that if they could fix the genetic flaw, or somehow stop the build-up of lipofuscin, they could stop the degeneration of photoreceptor cells and prevent further loss of vision.
Relative optimism in gene therapy trials
Stargardt's is a recessively inherited condition, which means you will only get the disease if you inherit the gene from both parents. The aim of the gene therapy will be to introduce the corrected gene into affected cells rather than to replace it. Scientists hope this will fix the genetic flaw and cure the disease.
They are hopeful because Stargardt's dystrophy is diagnosed in very young people and this is where gene therapy would be most effective. If successful, gene therapy would prevent the further degradation of photoreceptors in people with Stargardt's. But whether there would be an improvement in vision is still unknown.
There is still a lot more work to be done because although gene therapy tests in mice have shown great promise, studies on larger animals are needed before human trials can begin. But there is hope and researchers will continue to work on ways to fix the genetic flaw causing this condition.
More information on eye conditions
Our Helpline can provide support and advice on anything from eye conditions and available treatments through to emotional support and products that can make life easier for blind and partially sighted people. Email us at helpline@rnib.org.uk or call us on 0303 123 9999.