Clinical and mutational signatures of CRB1-associated retinopathies: a multicentre study

Background To delineate the clinical and mutational signatures of patients with CRB1-associated retinopathies. Methods This multicentre retrospective cohort study involved 40 patients with CRB1 mutations and 40 age-matched and gender-matched inherited retinal diseases (IRDs). The detailed phenotyping and genotyping characteristics and genotype‒phenotype correlations of the patients were analysed. Results The mean age of CRB1 cohort was 27.33±14.63 years. Results showed that yellowish geographic macular degeneration (66.67%), small white or yellow dots (65.6%), hyperopia (62.5%), abnormally laminated retina (61.61%), epiretinal membrane (60.6%) and nummular pigment deposits (50%) were the most common signatures in patients with CRB1 mutations. These clinical signatures were notably more prevalent among CRB1 patients than among individuals in other IRD groups (p<0.001). Early-onset severe retinal dystrophy/Leber congenital amaurosis (EOSRD/LCA) patients are more likely to present these signatures than retinitis pigmentosa (RP) and macular dystrophy (MD) patients. Furthermore, a significant reduction in central foveal thickness coupled with pronounced thickening of the peripheral retina was observed more distinctly in patients with EOSRD/LCA (p<0.001). The choroidal thickness was not significantly altered compared to the normal controls, but was markedly reduced in the other IRD groups (p<0.001). 55 pathogenic variants were identified, 20 of which were novel. Null mutations were associated with EOSRD/LCA patients, and missense mutations were more prevalent in MD and RP patients. Conclusions Key clinical and mutational signatures were demonstrated in this study, providing a comprehensive update on CRB1-associated retinopathies that will aid in diagnosis and lay the foundation for future therapeutic studies.