Stargardt

Stargardt disease, also known as Stargardt macular dystrophy or fundus flavimaculatus, is the most common inherited form of macular dystrophy. It is typically inherited in an autosomal recessive pattern and results from bi-allelic mutations in the ABCA4 gene, which encodes a transporter involved in clearing all-trans-retinal from photoreceptor outer segments after light exposure.

Pathophysiology is driven by ABCA4 mutations causing the accumulation of toxic retinoid compounds and lipofuscin within the retinal pigment epithelium (RPE). This buildup leads to RPE dysfunction and subsequent photoreceptor degeneration, with the central macula preferentially affected and central vision progressively impaired.

Clinical features commonly begin in adolescence or early adulthood. Patients experience gradual, bilateral loss of central vision, often with preserved peripheral vision. Fundus examination may reveal pisciform (fish-shaped) yellow-white flecks surrounding the fovea and, later, geographic atrophy of the macula. The historical term fundus flavimaculatus is used when flecks are present with little initial macular atrophy.

Diagnosis integrates imaging and genetic testing. Fundus autofluorescence typically shows hyperautofluorescent flecks and later hypoautofluorescent atrophic areas. Optical coherence tomography demonstrates disruption of the outer retinal layers, particularly the ellipsoid zone. Electroretinography may be normal early on but can decline as disease progresses, and genetic testing confirms ABCA4 mutations.

Management focuses on supportive care, including low-vision rehabilitation and genetic counseling. There is currently no cure, and high-dose vitamin A supplementation is discouraged due to the potential to worsen lipofuscin accumulation. Prognosis is variable; many individuals retain some vision into adulthood, but central vision can deteriorate over time. Stargardt remains the most common inherited macular dystrophy, with estimated prevalence around 1 in 8,000 to 10,000 people.