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A 50-year-old patient comes in for a routine exam. On fundus examination you notice the findings as shown above.

1.	Which of the following would be reasonable to include in your differential diagnosis?
	e -- all of the above The presence of the egg-yolk like lesions should suggest a vitelliform dystrophy. Given the age of the patient at presentation and the size of the egg-yolk lesion, adult vitelliform dystrophy would be higher on your differential compared to Best’s disease.  Given the presence of drusen surrounding the egg-yolk lesion, it would be reasonable to suspect age-related macular degeneration with choroidal neovascularization. Solar retinopathy can cause a yellow spot in the fovea.  Premacular hemorrhage should also be considered as a cause for these lesions, though it would be highly unlikely to have bilateral symmetric lesions secondary to a vasculopathy such as diabetes.
2.	If this were Best’s disease, to which layer of the eye would you localize this lesion?
	b -- retinal pigmented epithelium Best’s disease is due to a mutation in the VMD2 gene which encodes the protein bestrophin.  Bestrophin is a transmembrane chloride channel located in the baslateral plasma membreane of the retinal pigment epithelium (RPE).
3.	If this were Best’s disease, which stage of disease would you classify this as and what would you espect the patient’s vision to be?
	b -- vitelliform stage: 20/20 - 20/40 Despite the appearance of the macular lesions in Best’s disease, patients tend to maintain good vision unless they develop a choroidal neovascular membrane (~20%) or geographic atrophy as the yolk lesion breaks down.