OTC and retinitis pigmentosa: Other genes in close proximity to CYBB are RPGR encoding retinitis pigmentosa GTPase regulator (telomeric) associated with RPGR-related retinitis pigmentosa; DMD, encoding dystrophin (telomeric) associated with Duchenne muscular dystrophy; and OTC, encoding ornithine transcarbamylase (centromeric) associated with ornithine transcarbamylase deficiency [115].