BEST1 and Behcet disease: One of the more common early onset macular dystrophies, BD results from AD mutations in BEST1, the gene encoding bestrophin-1, whose product localizes to the basolateral plasma membrane of the RPE.[147] Progression of BD is classically described by five stages with variable rates of progression: previtelliform (subclinical), vitrelliform, pseudohypopyon, vitelliruptive, and atrophic/cicatricial.