Bestrophin-1 (Best1) is a protein that, in humans, is encoded by the BEST1 gene (RPD ID - 5T5N/4RDQ). The bestrophin family of proteins comprises four evolutionary related genes (BEST1, BEST2, BEST3, and BEST4) that code for integral membrane proteins. This family was first identified in humans by linking a BEST1 mutation with Best vitelliform macular dystrophy (BVMD). Mutations in the BEST1 gene have been identified as the primary cause for at least five different degenerative retinal diseases.