Is expressed in several structures, including eye; gonad; muscle; neural tube; and optic cup. Human ortholog(s) of this gene implicated in X-linked atrophic macular degeneration; X-linked cone-rod dystrophy 1; X-linked retinitis pigmentosa and sinorespiratory infections; retinitis pigmentosa; and retinitis pigmentosa 3. Orthologous to human RPGR (retinitis pigmentosa GTPase regulator).