RPGR and retinitis pigmentosa 1: Potentially consistent with other clinical findings of RP, some genes were also expressed in vascular endothelium and RGCs (e.g., RPGR and TOPORS), while others were expressed at highest levels in RGCs (e.g., SLC25A46, SLC7A14 and RP9) or Müller glia (e.g., RGR and RLBP1).