Stargardt disease is a genetic condition caused by a tiny alteration in a single gene. It is also known as fundus flavimaculatus and is the most common form of juvenile macular dystrophy.
Stargardt causes a wasting of a central area of the retina called the macula. This area is eventually surrounded by a ring of white or yellow spots. An important layer of the retina, the retinal pigment epithelium (RPE), is also affected by an accumulation of ‘waste’ material called lipofuscin.
How is Stargardt disease inherited?
Stargardt is a genetic condition, which is inherited as either a dominant or recessive form.
Stargardt disease is most often inherited as the recessive form. This is where the faulty gene is inherited from both parents. In a recessive condition the parents probably will not have the condition themselves although they both carry the faulty gene. With recessive inheritance, there is a 25 per cent chance of each child inheriting the condition. This chance is the same for each child whether they are male or female and regardless of the birth order. The gene associated with this form of Stargardt disease is called ABCA4 on chromosome 1.
Alterations in another gene called ELOVL4 cause a less common dominant form of the disease. In these cases the parent with the faulty gene will have the condition themselves and there is a 50 per cent chance that they will pass the gene on to each child they have. This chance is the same for each child whether they are male or female and regardless of the birth order.
What are the symptoms?
In the early stages, people may have good visual acuity, but may experience difficulty reading or seeing in dim light. Other common symptoms of Stargardt disease include blurriness and distortion of vision.
Children often first experience symptoms between the ages of 6 and 12. They may begin to find it difficult to adapt from dark to light or light to dark surroundings (known as ‘dark-adaptation’). However, some people do not have any symptoms until adulthood. Stargardt disease is usually diagnosed in people under the age of 20.
There is currently no treatment for Stargardt disease; however there is a wide range of support available as outlined below to help people with the condition as well as their family and friends. If you experience any sudden changes in vision seek urgent medical advice from an eye hospital.
There is a great deal of research going on into potential treatments. We are finding out more about genetics and gene-based therapies are being developed. Stem cell research is also encouraging.