Stargardt disease

It is an inherited disorder of the retina, typically causes vision loss during childhood or adolescence, although in some forms, vision loss may not be noticed until later in adulthood. It is rare for people with the disease to become completely blind. For most people, vision loss progresses slowly over time to 20/200 or worse.

Stargardt disease is also called Stargardt macular dystrophy, juvenile macular degeneration, or fundus flavimaculatus. The disease causes progressive damage—or degeneration—of the macula. Stargardt disease is one of several genetic disorders that cause macular degeneration.
The most common symptom of Stargardt disease is variable, often slow loss of central vision in both eyes. People with the disease might notice gray, black, or hazy spots in the center of their vision, or that it takes longer than usual for their eyes to adjust when moving from light to dark environments. Their eyes may be more sensitive to bright light. Some people also develop color blindness later in the disease.

The progression of symptoms in Stargardt disease is different for each person. People with an earlier onset of disease tend to have more rapid vision loss. Vision loss may decrease slowly at first, then worsen rapidly until it levels off. Most people with Stargardt disease will end up with 20/200 vision or worse.

Mutations in ABCA4 gene are the most common cause of Stargardt disease. This gene makes a protein that normally clears away vitamin A byproducts inside photoreceptors. Cells that lack the ABCA4 protein accumulate clumps of lipofuscin, a fatty substance that forms yellowish flecks. As the clumps of lipofuscin increase in and around the macula, central vision becomes impaired. Eventually, these fatty deposits lead to the death of photoreceptors and vision becomes further impaired.

Mutations in the ABCA4 gene are also associated with other retinal dystrophies including cone dystrophy, cone-rod dystrophy, and retinitis pigmentosa.

Lipofuscin deposits can be seen as yellowish flecks in the macula. The flecks are irregular in shape and usually extend outward from the macula in a ring-like pattern. The number, size, color, and appearance of these flecks are widely variable.

In fundus autofluorescence (FAF): This test can detect lipofuscin that might not be visible with standard fundus photography, making it possible to diagnose it.