BD is the second most common MD, affecting approximately 1 in 10 000.4 BD is an autosomal dominant condition associated with disease-causing variants in BEST1. 42BEST1 sequence variants also account for at least four other phenotypes, including adult vitelliform MD,43 autosomal dominant vitreochoroidopathy,44 autosomal recessive bestrophinopathy (ARB)45 and retinitis pigmentosa.46 Here, BEST1 is linked to autosomal recessive bestrophinopathy.