Author’s Disclosure Block: Shanone Dhanji, none; Kirk Stephenson, none; Kevin Gregory-Evans, none; Olubayo Kolawale, none; Cheryl Gregory-Evans, none

Abstract Body
Background: Inherited retinal degenerations (IRD) are clinically heterogeneous. The influence of ethnicity has not been clearly reported in IRD. 

Methods: A retrospective study was conducted assessing the three most common IRD genotypes (ABCA4, USH2A, RPGR). Clinical and genetic data were assessed between ethnic groups (Caucasian, East Asian, South Asian, Indigenous, African) and between Caucasians (largest group) and non-Caucasians. 

Results: Caucasians were over-represented (76%) compared with local population statistics (55%). For ABCA4, East Asians manifested a focal bullseye maculopathy most commonly, while classic Stargardt disease predominated in other ethnic groups; cataract was more prevalent in Caucasians than non-Caucasians (p=0.001). For USH2A, non-Caucasians were more likely to have non-syndromic IRD than Usher syndrome, while Caucasians had a 50% chance of each. A hyperautofluorescent macular ring was more common in non-Caucasians (p=0.027) with USH2A genotypes. In RPGR, VA was significantly worse for Caucasians (LogMAR 0.76 ±0.69) than non-Caucasians (0.49 ±0.30, p=0.047) and myopia was greater in South Asians (-9.56 ±0.27 D) than all other ethnic groups (-3.82 ±4.05 D, p<0.001). Genetic variants were only shared between ethnic groups in 3.3% (5/135) variants. Discussion: Clinical and genetic differences are apparent between ethnic groups, even within the three most common IRD genotypes. This has an impact on accuracy and time to diagnosis with knock-on effects to clinical care including access to novel therapies. Further work to expand the genetic reference databases for non-Caucasian ethnic groups is needed to facilitate equitable access to diagnosis and treatment.