Introduction: Macular dystrophies encompass a group of inherited retinal disorders characterized by progressive degeneration of the macula, leading to central vision loss. Among these, Stargardt disease and Best disease are two well-known entities with distinct clinical features, genetic etiologies, and prognoses.

Stargardt Disease:

• Clinical Features:
  • Stargardt disease, also known as Stargardt macular dystrophy (SMD) or fundus flavimaculatus, typically manifests in childhood or adolescence.
  • Patients present with bilateral central vision loss, impaired color vision, and central scotoma.
  • Fundoscopic examination reveals characteristic findings such as yellow-white flecks at the level of the retinal pigment epithelium (RPE) and macular atrophy.
• Genetics:
  • Stargardt disease is primarily caused by mutations in the ABCA4 gene, encoding a protein involved in the visual cycle and photoreceptor function.
  • Both autosomal recessive and, less commonly, autosomal dominant inheritance patterns have been reported.
• Management:
  • Currently, there is no cure for Stargardt disease. Management focuses on optimizing visual function and preventing disease progression.
  • Low vision aids, including magnifiers and electronic devices, can aid in visual rehabilitation.
  • Research into potential treatments, such as gene therapy and pharmacological interventions, is ongoing.

Best Disease (Best Vitelliform Macular Dystrophy):

• Clinical Features:
  • Best disease typically presents in childhood or early adulthood, although age of onset can vary widely.
  • Patients initially exhibit a characteristic egg yolk-like macular lesion known as a vitelliform or Best’s egg.
  • Over time, the lesion may progress through various stages, including pseudohypopyon, vitelliruptive, atrophic, and choroidal neovascularization stages.
• Genetics:
  • Best disease is caused by mutations in the BEST1 gene, encoding the bestrophin-1 protein, which is involved in calcium-activated chloride channel function in the RPE.
  • It follows an autosomal dominant inheritance pattern, with variable penetrance and expressivity.
• Management:
  • Treatment options for Best disease are limited, and management focuses on monitoring disease progression and addressing complications such as choroidal neovascularization.
  • Intravitreal anti-vascular endothelial growth factor (anti-VEGF) injections may be considered for associated neovascularization.
  • Genetic counseling is recommended for affected individuals and their families to discuss inheritance patterns and recurrence risks.

Conclusion: Stargardt disease and Best disease are two distinct forms of inherited macular dystrophies with unique clinical presentations, genetic underpinnings, and management approaches. Despite advances in understanding these conditions, effective treatments remain elusive, highlighting the need for ongoing research and therapeutic innovation.

Links:

• Foundation Fighting Blindness: Stargardt Disease
• National Institutes of Health (NIH): Best Disease