USH2A and cone-rod dystrophy: Causative genes including EYS, USH2A, RP1, CNGA1, CNGB1, PRPF6, PRPF31, SNRNP20 was detected in 28 patients with RP (n = 15, 6, 2, 1, 1, 1, 1, 1, respectively), and GUCY2D, PRPH2 were detected in two patients with CRD (n = 1, 1).