XLRP accounts for about 10–15% of all retinitis pigmentosa cases and is primarily associated with mutations in the RPGR (retinitis pigmentosa GTPase regulator) and RP2 (retinitis pigmentosa 2, activator of ARL3 GTPase) genes, which play a fundamental role in maintaining photoreceptor structure and function [4,5,6,7]. The gene discussed is RPGR; the disease is retinitis pigmentosa.