In this study, RPGRIP1, RANBP2, NPM1, PDE6D, NPHP5, and ABCA4 genes were selected on the basis of interaction with RPGR or RPGRIP1 or their implication in related retinal diseases, and were investigated as candidate genetic modifiers of XLPRA1. The gene discussed is ABCA4; the disease is Abnormal retinal morphology.