Disease progression of retinitis pigmentosa caused by PRPF31 variants in a Nordic population: a retrospective study with up to 36 years follow-up.

ABSTRACT

BACKGROUND/AIMS: To investigate the natural history of PRPF31-related retinitis pigmentosa (RP11). MATERIALS AND METHODS: We identified individuals with RP11 and collected retrospective data from disease onset to present date including genetics, demographic data, Goldmann visual field areas, and visual acuity measurements. Visual fields were evaluated as summed squared degrees and best-corrected visual acuity was converted to logMAR. We performed linear mixed model regression analysis to evaluate annual disease progression, and survival analysis to evaluate the age of legal blindness. RESULTS: We included 46 subjects with RP11. Median age of disease onset was 10 years (range 5-65). Follow-up spanned from 0 to 36 years with a median of 8 years. Median Goldmann visual field areas decreased by 10.0% per year (95% CI 7.5%-12.4%) with target IV4e, 7.9% (95% CI 4.5% - 11.2%) with target III4e, and 9.3% (95% CI 7.0% -11.5%) when combining target sizes. Individuals with RP11 maintained good visual acuity until late stage of disease. Legal blindness was reached at a median age of 57 years (95% CI 50-75 years). CONCLUSIONS: PRPF31 variants cause autosomal dominant retinitis pigmentosa that most commonly manifests in childhood with a variable disease progression. Visual field area deteriorates faster than visual acuity and was the major cause of legal blindness in our study population. This study characterizes disease progression in retinitis pigmentosa caused by PRPF31-variants and demonstrates the importance of differentiation between specific genotypes when counselling patients and conducting natural history studies of RP.