"Genetic and clinical findings in an ethnically diverse retinitis pigmentosa cohort associated with pathogenic variants in EYS".

BACKGROUND AND OBJECTIVES: The EYS gene is an important cause of autosomal recessive retinitis pigmentosa (arRP). The objective of this study is to report on novel pathogenic variants in EYS and the range of associated phenotypes. SUBJECTS AND METHODS: This retrospective case series at a tertiary referral centre for inherited retinal diseases describes patients with an IRD and at least two variants in the EYS gene. Phenotyping included multimodal retinal imaging; genotyping molecular genetic analysis using targeted next generation sequencing. Sanger sequencing verification and analysis of novel variants using in silico approaches to determine their predicted pathogenicity. RESULTS: Eight male and four female patients were included. Age at onset ranged from 11 to 62 years with variable symptom presentation; ten patients showed classical features of retinitis pigmentosa, albeit with great variation in disease severity and extent. Two patients had atypical phenotypes: one with localised inferior sector pigmentation and a mild RP phenotype with changes predominantly at the posterior pole. Eighteen variants in EYS were identified, located across the gene: six were novel. Eight variants were missense, two altered splicing, one was a whole exon duplication and the remainder were predicted to result in premature truncation of the protein. CONCLUSION: The marked variability in severity and age of onset in most patients in this ethnically diverse cohort adds to growing evidence that that mild phenotypes are associated with EYS variants. Similarly, the two atypical cases add to the growing diversity of EYS disease as do the six novel pathogenic variants described.