BEST1 and adult-onset foveomacular vitelliform dystrophy: Mutations in BEST1 are associated with phenotypic heterogeneity and cause five clinically distinct human diseases—the classical BVMD, adult-onset vitelliform macular dystrophy (AVMD), autosomal dominant vitreoretinochoroidopathy (ADVIRC), autosomal recessive bestrophinopathy (ARB) [7] and retinitis pigmentosa (RP) [8–10].