RHO and retinitis pigmentosa 1: However, a recent study also noted the double hyper-AF ring in a patient with RHO-linked RP and a patient with RPGR-linked RP, as well as significant overlap in other FAF patterns among genotypes.[174] Although many patterns of FAF have been described in RP, and some show predilection for certain genes, it is difficult to determine the RP genotype by FAF pattern alone.