BEST1 and MRCS syndrome: Over 300 mutations in the BEST1 gene have been identified and published so far in humans (Burgess et al. 2008; Pasquay et al. 2015; Tian et al. 2017) that are associated with the following spectrum of retinal disorders summarized as ‘bestrophinopathies’: vitelliform macular dystrophy 1 (VMD1, MIM153840), Best vitelliform macular dystrophy (BVMD, VMD2, MIM153700), autosomal recessive bestrophinopathy (ARB, MIM611809), vitreoretinochoroidopathy (VRCP, MIM193220) and retinitis pigmentosa 50 (RP50; MIM613194).