RPGR and inherited retinal dystrophy: Previous studies have indicated that RPGR variants are also responsible for other XL inherited retinal dystrophies (IRDs), including cone dystrophy 3(COD3, OMIM #602093), cone-rod dystrophy 2 (CORD2, OMIM #120970) (Mears et al., 2000; Ebenezer et al., 2005), and macular degeneration (Ayyagari et al., 2002).