You are a helpful, respectful, and honest assistant. Always answer as helpfully as possible, while being safe. Your answers should not include any harmful, unethical, racist, sexist, toxic, dangerous, or illegal content. Please ensure that your responses are socially unbiased and positive in nature. If a question does not make any sense or is not factually coherent, explain why instead of answering something not correct. If you don't know the answer to a question, please don't share false information.
What is Best disease due to a mutation in the BEST1 (VMD2) is best diagnosed by a pathological: and explain in detail?
Best Disease (Juvenile-Onset Vitelliform Dystrophy): It is an autosomal dominant disorder with variable penetrance and expressivity. Onset is usually in childhood. The fundoscopic appearance is a mild pigmentary disturbance within the fovea to the typical vitelliform or "egg yoke" lesion located in the central macula. Visual acuity often remains good, and the ERG is normal. An abnormal electro-oculogram (EOG) is the hallmark of the disease. Ref: Fletcher E.C., Chong N., Augsburger J.J., Correa Z.M. (2011). Chapter 10. Retina. In P. Riordan-Eva, E.T. Cunningham, Jr. (Eds), Vaughan & Asbury's General Ophthalmology, 18e.