Stargardt Disease. What Is It?
Stargardt disease is a rare inherited genetic disease that occurs when fatty material accumulates in the macula, a vital part of the retina that facilitates central vision. It is the most common form of juvenile macular degeneration and is estimated to affect 1 in every 8,000 to 10,000 people. It often develops during childhood, leading to progressive vision loss to the point of blindness during adulthood.
Stargardt disease has several effects on the eye, with the most prominent symptom being central vision loss. Central vision is the ability to clearly see details of objects directly in front of you. Other symptoms may appear as well, including increased sensitivity to light, colour blindness and the loss of peripheral vision.
The root of Stargardt disease is a genetic mutation in the ABCA4 gene, a gene that creates the required proteins for transporting unwanted byproducts out of photoreceptor cells. These byproducts are created during a process called phototransduction, where photoreceptor cells convert light into electrical signals for the brain. When this toxic waste is unable to be transported out of the cells, it builds up and forms lipofuscin, a type of fatty material, and the formation of lipofuscin in the photoreceptor cells and surrounding retina cells eventually causes the cells to die. Lipofuscin is also formed after the making of cells using vitamin A.
Currently, there is no treatment for Stargardt disease, however, preventative measures can be taken to slow down the rate of vision loss. Excessive exposure to light will cause damage to the retina, thus, it is recommended that you bring a hat or pair of sunglasses when going outside to prevent further damage. It is also advised to not take supplements containing more than the recommended amount of vitamin A. This is because more vitamin A may cause more lipofuscin to accumulate, thereby accelerating the disease’s severity.
Promising gene and drug therapies are also being researched in hopes of providing a concrete treatment for Stargardt disease. One such treatment involves delivering a healthy version of the ABCA4 gene into retinal cells so that the correct protein can be synthesised. Another study involves replacing dead photoreceptor cells with functioning ones derived from stem cells, which are cells that can turn into many different specialised types of cells. Additionally, another possibility involves the production of a drug that can reduce the buildup of lipofuscin in the macula. Overall, while there is yet to be an official and widespread treatment for this genetic disease, study and research shows a very bright path ahead of us.