CRB2 and cone-rod dystrophy: Mutations in the Crumbs homolog 1 (CRB1) gene are associated with retinitis pigmentosa (RP), Leber congenital amaurosis (LCA), and cone-rod dystrophies and are sporadically found in foveal retinoschisis and macular dystrophy.1, 2, 3 The human and nonhuman primate retina express and localize CRB1 and CRB2 proteins in Müller glial cells (MGCs) and photoreceptor cells (PRCs) at the outer limiting membrane (OLM).4, 5, 6 The mouse retina also expresses and localizes the CRB2 protein at the OLM in MGCs and PRCs.