Best Vitelliform Macular Dystrophy (Best Disease)
A rare inherited retinal disease that primarily affects the macula, the central area of the retina responsible for detailed vision.
Understanding Best Disease and Related Bestrophinopathies
Best disease, also known as Best vitelliform macular dystrophy, is the most common inherited disorder caused by changes in the BEST1 gene. It belongs to a group of rare genetic eye conditions known collectively as bestrophinopathies.
The BEST1 gene produces a protein called bestrophin-1, which is essential for maintaining the health of the retinal pigment epithelium, a layer of cells that supports the retina. When this protein does not function properly, retinal cells can become damaged over time, leading to vision changes and, in some cases, progressive sight loss.
Best disease typically develops during childhood or adolescence and is characterised by a distinctive yellow deposit in the centre of the retina that resembles an egg yolk. While many individuals maintain good vision for years, some experience gradual central vision loss as the disease progresses.
Other BEST1-related conditions include autosomal recessive bestrophinopathy, autosomal dominant vitreoretinochoroidopathy, and microcornea, rod-cone dystrophy, early-onset cataract, and posterior staphyloma syndrome.
1 in 16,500–21,000
Estimated prevalence (US study)
1
Established disease-causing gene
69 BEST1
Variants identified in a large study
How Best Disease can affect vision
Blurred central vision
Damage to the macula may cause difficulty with detailed vision tasks such as reading small print or recognising faces.
Distorted vision, where straight lines appear wavy
Straight lines may appear bent or wavy due to changes affecting the macula (Metamorphopsia).
Central blind spots
Some people develop areas of reduced or missing vision in the centre of their visual field.
Gradual decline in visual acuity
As the disease progresses, sharpness of vision may decline.
Reduced ability to see fine details
Difficulty in seeing the smaller, finer details of objects and environments.
Identifying Best Disease
Eye examination
An ophthalmologist examines the retina and may identify characteristic vitelliform deposits.
Retinal imaging
Including:
Fundus photography
Provides images of retinal changes and characteristic deposits.
Optical coherence tomography (OCT)
Provides detailed cross-sectional images of retinal layers and helps monitor disease progression.
Fundus autofluorescence (FAF)
Helps identify areas of lipofuscin accumulation within retinal cells.
Electro-oculography (EOG)
EOG measures the function of the retinal pigment epithelium and can provide important information in Best Disease.
Genetic testing
Testing for changes in the BEST1 gene can confirm diagnosis.
A genetic diagnosis can support:
- Accurate classification of the condition
- Family counselling
- Research participation
- Understanding future treatment opportunities
Supporting vision and managing complications
Regular monitoring
Routine eye examinations help track changes in the retina and identify complications.
Low vision support
People experiencing vision loss may benefit from:
- Magnification devices
- Assistive technology
- Accessibility tools
- Vision rehabilitation services
Managing complications
Some complications may be treated with specific therapies.
For example:
- Abnormal blood vessel growth beneath the retina may be treated with anti-VEGF therapies.
Treatment decisions depend on the individual’s symptoms and clinical findings.
Genetic counselling
Genetic counselling can help individuals and families understand:
- Inheritance patterns
- Family risks
- Testing options
Emerging therapies
Best disease (Best vitelliform macular dystrophy) currently has no approved cure, but several promising therapies are under development. The most advanced approach is gene therapy, particularly OPGx-BEST1, a one-time subretinal treatment designed to restore the function of the defective BEST1 gene. In 2025, the first patient was dosed in a Phase 1/2 clinical trial, representing a significant milestone for individuals affected by this inherited retinal disease. Early clinical results reported in 2026 showed that the therapy was well tolerated, with no treatment-related serious adverse events and encouraging signs of improved visual function and retinal structure in the treated patient. In addition to gene replacement therapy, researchers are investigating CRISPR-based gene editing techniques that aim to directly correct disease-causing BEST1 mutations. Scientists are also exploring gene augmentation strategies, which involve delivering a healthy copy of the BEST1 gene to retinal cells to restore normal function. Although these therapies remain experimental, they offer hope that effective treatments for Best disease may become available in the future.
Adapting to changes in central vision
Most people with Best disease maintain useful vision for many years and continue to live active, independent lives. While vision changes may occur over time, practical support and regular specialist care can make a significant difference.
Common challenges may include:
- Difficulty reading small print
- Reduced ability to see fine detail
- Distorted central vision
- Difficulty recognising faces at a distance
- Challenges performing tasks that require sharp central vision
- Concerns about future vision changes
Helpful support strategies include:
- Regular appointments with a retinal specialist
- Magnification devices and electronic reading aids
- Good lighting at home, school, and work
- Accessibility features on smartphones, tablets, and computers
- Low vision rehabilitation services
- Educational accommodations for children and young people
- Workplace adjustments when required
- Genetic counselling for affected families
- Support groups and patient organisations
Beyond Best Disease
Although Best disease is the most common form, BEST1 mutations can also cause several rarer disorders:
- Autosomal recessive bestrophinopathy, which often presents with widespread retinal changes and fluid accumulation beneath the retina.
- Autosomal dominant vitreoretinochoroidopathy, a rare condition affecting the peripheral retina.
- Microcornea, rod-cone dystrophy, early-onset cataract, and posterior staphyloma syndrome, which affects multiple structures within the eye and can lead to significant visual impairment.
Together, these conditions are referred to as bestrophinopathies.
Most Common BEST1 Condition
Best Vitelliform Macular Dystrophy
The most frequently diagnosed bestrophinopathy worldwide
250+
Known disease-causing mutations in the BEST1 gene
1 Shared Hallmark
Abnormal electro-oculogram findings across almost all BEST1-related disorders
For children diagnosed with Best disease, early educational support can help ensure they reach their full potential. Adults may benefit from assistive technologies and workplace accommodations that help maintain independence and productivity.
Importantly, many people with Best disease continue to study, work, travel, raise families, and participate fully in everyday life.
Useful External Resources
Advancing the future of Best Disease treatment
Gene therapy
Understanding disease mechanisms: Researchers continue to study how BEST1 gene changes affect retinal cells and contribute to disease progression.
Because Best Disease is associated with a specific gene, researchers are exploring approaches that may target the underlying genetic cause.
Retinal cell therapies
Retinal cell therapies explore the replacement or regeneration of damaged retinal cells to help restore visual function.
Retinal prostheses and vision restoration technologies
Retinal prostheses and vision restoration technologies use innovative devices and technologies to stimulate remaining retinal pathways and support vision.
Natural history studies and registries
Natural history studies and registries collect long-term data to better understand how Best Disease progresses and to guide future treatment development.
Clinical trials
Clinical trials evaluate the safety and effectiveness of new therapies, medicines, and technologies for people living with Best Disease.
Information and community support
Take the Next Step
Best Vitelliform Macular Dystrophy highlights the importance of genetic understanding, early diagnosis, and patient-centred research in advancing the future of retinal health.
Through collaboration between people affected by Best Disease, researchers, clinicians, and organisations worldwide, progress continues towards improved support, better understanding, and new treatment possibilities.
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