Relationship between macular curvature and common causative genes of retinitis pigmentosa in Japanese patients

PURPOSE. To determine the relationship between the macular curvature and the causative genes of retinitis pigmentosa (RP). METHODS. We examined the medical records of the right eyes of 65 cases with RP (31 men and 34 women; average age, 47.6 years). There were 31 cases with the EYS variants, 11 cases with the USH2A variants, six cases with the RPGR variants, 13 cases with the RP1 variants, and four cases with the RP1L1 variants. The mean curvature of Bruch’s membrane was calculated within 6 mm of the fovea as the mean macular curvature index (MMCI, 1/μm). We used multiple linear regression analysis to determine the independence of the causative genes contributing to the MMCIs after adjustments for age, sex, axial length, and width of the ellipsoid zone. RESULTS. The median MMCI was -31.2 × 10^-5/μm for the RPGR eyes, -16.5 × 10^-5/μm for the RP1L1 eyes, -13.0 × 10^-5/μm for the RP1 eyes, -9.8 × 10^-5/μm for the EYS eyes, and -9.0 × 10^-5/μm for the USH2A eyes. Compared with the EYS gene as the reference gene, the RPGR gene was significantly related to the MMCI values after adjusting for the other parameters (P = 5.30 × 10^-6). In contrast, the effects of the other genes, USH2A, RP1, and RP1L1, were not significantly different from that of the EYS gene (P = 0.26, P = 0.49, and P = 0.92, respectively). CONCLUSIONS. The RPGR gene had a stronger effect on the steep macular curvature than the other ciliopathy-related genes.