OBJECTIVES: Inherited retinal dystrophies (IRDs) are a heterogeneous group of diseases resulting from over 220 genetic mutations and are generally characterized by retinal degeneration ultimately leading to severe visual impairment or blindness. The aim of this study was to collect epidemiology data on RPE65 mutation associated IRDs, most often reported as Leber Congenital Amaurosis 2 (LCA2) and Retinitis Pigmentosa 20 (RP20).

METHODS: Publications were reviewed up to March 2018 in MEDLINE, Embase, and Cochrane. Data collected included the prevalence and incidence of RP and LCA, and the proportion caused by RPE65 mutations within each disease. A quality assessment was conducted, and low ranked studies were excluded from the analysis.

RESULTS: From the 2,571 citations screened, 49 studies presented relevant epidemiology data. The prevalence of LCA and RP ranged between 1 in 81,000 and 1 in 33,000, and between 1 in 8,357 and 1 in 3,454 respectively. There is a scarcity of incidence data for RP (Korea has 1.64 in 100,000 cases per year and US has 0.6 in 100,000 cases per year) and no data sources were found for LCA. The proportion of RPE65 mutations in LCA and RP patients varied from 1.0% to 16.6% and 1.0% to 6.0%, respectively. Regarding LCA, the proportion of RPE65 mutations ranged between 2.38% and 16% in Europe, 3.8% and 16% in the US, and 1% to 16.6% in the rest of the world. The proportion of RPE65 mutations in RP patients ranged between 1.8% and 6% in European countries, while in the US, the proportion ranged between 1.0% and 3.0%.

CONCLUSIONS: Data on prevalence and incidence of RPE65 is scarce but indicates significant variation among countries. Further research is needed to generate consistent epidemiology figures for RPE65 mutation associated IRDs.