Stargardt Disease

Stargardt disease is an inherited retinal disease that causes progressive vision loss, affecting between 1 in 8,000 to 1 in 10,000 people (1). Vision loss typically begins during childhood or adolescence, with symptoms similar to age-related macular degeneration (AMD). Since symptoms usually begin at a younger age, Stargardt disease is sometimes called juvenile macular degeneration.

Stargardt disease affects the macula, the small central portion of the retina, leading to loss of central vision over time, and is caused by the death of light-sensing photoreceptor cells in the retina. Photoreceptor cells sense light and then send signals to the brain to create images. There are two types of photoreceptor cells:

Rods, responsible for peripheral and night vision
Cones, responsible for central and detail vision

In Stargardt disease, both rods and cones die but cone cells are more strongly affected.

Genetics

Stargardt disease is a genetic or inherited disease caused by mutations in genes. 95% of cases are caused by mutations in the ABCA4 gene. Mutations in ELOVL4, STGD4, and PRPH2 can also cause Stargardt disease.

Individuals receive two copies of every gene: one from the mother and one from the father. Stargardt disease is an autosomal recessive disorder which means that both copies of the gene (e.g., ABCA4) have a mutation. For more information about genes visit our genetic testing page.

How ABCA4 mutations cause Stargardt disease

Genes give cells instructions to produce proteins which carry out cellular functions. The ABCA4 protein removes a toxic substance called lipofuscin from the photoreceptors and surrounding cells. When the ABCA4 gene is mutated, the ABCA4 protein is not made properly and cannot carry out its role of removing lipofuscin from the eye. This causes lipofuscin to build up and over time damages the photoreceptors, eventually leading to central vision loss (2).

Symptoms

Stargardt disease primarily affects central vision, leaving peripheral vision often unaffected.

Symptoms include:

Loss of central vision in both eyes (may be uneven between eyes)
Blurry, black, or grey spots in the centre of visual field
Light sensitivity (photophobia)
Colour blindness, especially later in the disease

Symptoms of Stargardt disease usually begin in childhood or young adulthood, though some forms of the disease may begin after age 45 (3). Vison loss occurs over time and can be fast or slow depending on individual factors. People who develop symptoms earlier often have faster vision loss. People with advanced Stargardt disease usually have a visual acuity between 20/70 and 20/200 (4). For more information on visual acuity, visit our “how the eye works” page.

DIAGNOSIS

There are several tests your eye doctor will perform to diagnose Stargardt disease and measure vision loss.

During an eye exam, your doctor will examine the retina. You will get drops in your eye that dilate the pupils to see the retina. People who have Stargardt disease have yellow spots on their macula. These yellow spots are made of lipofuscin. Lipofuscin build-up increases as Stargardt disease progresses.

Your doctor may do a fluorescein angiography. This test shows the blood vessels in your eye and identifies any damaged areas. This test takes about 30 minutes. Your doctor will inject a yellow dye into a vein in your arm and then dilate your eyes. This dye will circulate through your body and once it reaches your eye, the doctor will take a photo of your retina. This test is safe and causes minimal discomfort. People who have Stargardt disease will have a dark area in the retina.(5)

Along with these tests, your doctor will measure your visual acuity (how sharp your vision is) and talk to you about other symptoms you may be experiencing.

When Stargardt disease is suspected, your doctor may order genetic tests to confirm the diagnosis. People with a family history of Stargardt disease may also consider genetic counselling.

Treatment

Currently, no treatment exists to reverse or slow the progression of Stargardt disease, though researchers are investigating several potential treatments (6). Research shows small to moderate effects of certain lifestyle changes in slowing the degeneration of photoreceptors.

Lifestyle Changes

Wearing sunglasses that block 100% of UV light and hats outdoors may reduce the build-up of lipofuscin.

There is some limited research suggesting that high doses of vitamin A might increase the build-up of lipofuscin. In a 2016 study, people with Stargardt disease who had lower vitamin A intake had better visual acuity than those with a higher intake. If you have Stargardt disease, speak with your eye doctor about your vitamin A intake.

Resources

Do you have questions about your eye health or information shared on this page? Our Health Information Line is here to support you. For resources on how to monitor your risk to prevent sight loss, check out the following resources:

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References

Updated on July 22, 2019.

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