Nationwide prevalence assessment of inherited retinal diseases in the Israeli population

Abstract

Purpose : Inherited retinal diseases (IRDs) are a group of over 50 clinically and genetically heterogeneous diseases. The information that is currently available regarding the prevalence of various IRDs is limited and varies between different populations. Moreover, nationwide prevalence studies are rare and usually limited to a specific IRD phenotype. This might lead to inaccurate prevalence estimations that are being cited in the scientific literature. Therefore, we wanted to estimate the prevalence of IRDs in the Israeli population.

Methods : We collected nationwide data regarding the number of individuals affected with IRD phenotypes assessed in clinical and academic centers in Israel as part of the research activity of the Israeli inherited retinal disease consortium (IIRDC). Individuals residing in Israel who received an IRD diagnosis by an ophthalmologist using either electroretinography (ERG) or retinal imaging were included. In addition, we recorded the number of affected siblings who did not have a comprehensive clinical evaluation. This allowed us to estimate a prevalence interval for each phenotype. Demographic information was collected from the Israeli central bureau of statistics and population size was set to 9,802,000 residents as of September 2023.

Results : Our records indicate that 7,850 individuals with IRDs were clinically diagnosed by ophthalmologists, whereas additional 1,546 family members were reported to have the same disease, but no ERG/imaging results could be obtained. Therefore, we set the threshold for the number of IRD cases in Israel between 7,850 and 9,396 affected individuals. This is translated to a prevalence of all IRDs combined ranging from 1:1,043 to 1:1,249. Figure 1 presents the most common IRDs in the Israeli population with retinitis pigmentosa being the most common one with a prevalence of ∼1:2,400 individuals, followed by cone-rod dystrophy (~14,000), Stargardt disease (∼1:16,000), Usher syndrome (∼1:16,000), and congenital stationary night blindness (∼1:18,000).

Conclusions : The current comprehensive study provides the largest prevalence dataset of all IRD phenotypes (n=67), some of which are extremely rare with only a single identified case. This analysis highlights the importance of performing additional nationwide prevalence studies in other countries in order to fully determine the prevalence of IRDs worldwide.

This abstract was presented at the 2024 ARVO Annual Meeting, held in Seattle, WA, May 5-9, 2024.