Summary about Disease
Best's vitelliform macular dystrophy (Best disease) is a genetic eye disorder that affects the macula, the central part of the retina responsible for sharp, central vision. It typically begins in childhood or adolescence but can sometimes present later in life. The hallmark of Best disease is the accumulation of yellowish, egg-yolk-like material (lipofuscin) under the macula. This accumulation can disrupt the function of the retinal pigment epithelium (RPE), which supports the photoreceptor cells responsible for vision. Best disease progresses through various stages, each characterized by different changes in the appearance of the macula and varying degrees of vision loss.
Symptoms
Symptoms vary depending on the stage of the disease. Some individuals may have normal vision initially, while others experience symptoms early on. Common symptoms include:
Blurred or distorted central vision
Difficulty reading fine print
Difficulty recognizing faces
Reduced color vision
A gray, black, or blank spot in the center of vision (scotoma)
Metamorphopsia (distortion of straight lines)
In some cases, complete loss of central vision may occur.
Causes
Best disease is caused by mutations in the BEST1 gene (formerly known as *VMD2*) located on chromosome 11q13. This gene provides instructions for making bestrophin-1, a chloride channel protein important for the function of the RPE. Mutations in *BEST1* disrupt the function of bestrophin-1, leading to the accumulation of lipofuscin under the macula. Best disease is typically inherited in an autosomal dominant pattern, meaning that only one copy of the mutated gene is needed to cause the disorder. However, spontaneous mutations can also occur.
Medicine Used
4. Medicine used There is currently no cure for Best disease. Treatment focuses on managing complications and maximizing remaining vision.
Anti-VEGF injections: If choroidal neovascularization (CNV) develops (growth of new blood vessels under the retina), anti-VEGF (vascular endothelial growth factor) injections may be used to reduce blood vessel growth and leakage.
Photodynamic therapy (PDT): In some cases of CNV, PDT may be used to destroy abnormal blood vessels.
Low vision aids: Magnifiers, special lighting, and other low vision aids can help people with Best disease maximize their remaining vision.
Is Communicable
No, Best disease is not communicable. It is a genetic disorder caused by mutations in a gene. It cannot be spread from person to person.
Precautions
Since Best disease is genetic, there are no specific precautions to prevent its occurrence. However, individuals with a family history of Best disease may consider:
Genetic counseling: Genetic counseling can help individuals understand their risk of inheriting or passing on the gene mutation.
Regular eye exams: Regular eye exams can help detect Best disease early and monitor its progression.
Protecting vision: Wearing sunglasses to protect the eyes from harmful UV rays and eating a healthy diet rich in antioxidants may help support overall eye health.
How long does an outbreak last?
Best disease is not an outbreak. It is a progressive, chronic condition. The timeline of symptom progression can vary significantly from person to person, spanning decades. There isn't a defined "outbreak" period.
How is it diagnosed?
Best disease is typically diagnosed through a comprehensive eye exam, including:
Visual acuity testing: To measure how well a person can see at different distances.
Dilated eye exam: To examine the retina and macula.
Optical coherence tomography (OCT): To create detailed images of the retina and macula.
Fluorescein angiography: To visualize blood vessels in the retina and macula.
Electrooculogram (EOG): To measure the electrical activity of the RPE. A decreased Arden ratio on the EOG is a classic finding in Best disease.
Electroretinogram (ERG): To measure the electrical activity of the photoreceptor cells. The ERG is usually normal in Best disease, helping to differentiate it from other retinal disorders.
Genetic testing: To confirm the diagnosis and identify the specific BEST1 mutation.
Timeline of Symptoms
The timeline of symptoms varies greatly, but the disease progresses through stages:
Stage 0 (Previtelliform): Normal fundus appearance. Abnormal EOG.
Stage 1 (Vitelliform): Egg-yolk lesion appears in the macula. Vision may be relatively normal.
Stage 2 (Pseudohypopyon): The egg-yolk lesion partially reabsorbs, creating a layered appearance.
Stage 3 (Vitelliruptive/Scrambled Egg): The egg-yolk material breaks up and becomes more scattered.
Stage 4 (Atrophic): The egg-yolk material disappears, leaving behind atrophy of the RPE. Vision loss is more significant.
Stage 5 (Choroidal Neovascularization (CNV)): New blood vessels grow under the retina, leading to leakage and bleeding. This can cause sudden vision loss. Not everyone progresses through all stages, and the rate of progression varies.
Important Considerations
Best disease is a progressive condition, and the degree of vision loss varies significantly.
Early diagnosis and regular monitoring are important to manage complications.
Genetic testing can help confirm the diagnosis and identify family members who may be at risk.
Low vision aids and rehabilitation services can help people with Best disease maximize their remaining vision and maintain their quality of life.
Support groups and online communities can provide emotional support and practical advice for people with Best disease and their families.
Research is ongoing to develop new treatments for Best disease.