Best disease, or vitelliform macular dystrophy, is a rare bilateral macular dystrophy with autosomal dominant inheritance characterized by subretinal accumulation of yellowish material in the macular area. Penetrance and clinical expression of Best disease vary greatly from one individual to another. Onset may occur in childhood or decades later. The typical vitelliform lesion shows an egg yolk-like appearing macular cyst measuring 0.5-3.0 disc diameters in size, and often has an asymmetric presentation. However, macular findings range from a small yellow spot, multiple vitelliform or atrophic lesions to a chorioretinal scar. Patients may complain of blurred vision, poor visual acuity, or metamorphopsia. The disease is slowly progressive and eventually results in atrophy of the retinal pigment epithelium (RPE) and photoreceptors, severely impairing central vision. Generally, orientation is normal and in most cases magnifying devices enable reading. Visual acuity cannot be predicted from the appearance of the macula. In typical Best disease the electro-oculogram (EOG) is usually abnormal, even in asymptomatic patients. Fluorescein angiography, RPE autofluorescence, OCT (optical coherence technology), full-field and multifocal electroretinogram (ERG) might add information for the correct diagnosis. Mutations in the VMD2 gene, mapped to 11q13, have been associated with Best disease. To date, there is no treatment for this disorder.
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