Abstract
Purpose :
The PRPH2 gene plays a role in the morphogenesis and stabilization of the outer segment of photoreceptors. Mutation in this gene causes a lot of distinct clinical diagnosis, such as pattern dystrophy, butterfly-shaped pattern dystrophy, central areolar dystrophy, adult-onset vitelliform macular dystrophy, retinitis pigmentosa, cone-rod dystrophy, retinitis punctata albescens, Leber congenital amaurosis, fundus flavimaculatus and Stargardt disease. This study is an observational clinical research of Brazilian patients with pathogenic variants in the PRPH2.
Methods :
This is a retrospective study of patients who had the molecular diagnosis defined by pathogenic variants in the PRPH2 gene from the analysis of the Federal University of São Paulo and the Institute of Ocular Genetics database from 1,246 Brazilian patients suffering from Inherited Retinal Disease between 1998 to 2018. Out of this total of 1,246 patients, 559 have undergone different commercial molecular tests, 159 being inconclusive or negative. Variables such as sex, age, clinical diagnosis, visual acuity, pathogenic variants, zygosity have been analyzed.
Results :
Eight patients (2%) with retinopathies related to PRPH2 mutations were found. The clinical diagnosis was: best disease, cone dystrophy, early onset retinal dystrophy, retinitis pigmentosa and Stargardt disease. The average age was 41,25 (from 15 to 60 years) and 63% were female. The Visual Acuity varied from 20/25 to 10/400. The pathogenic variants found were: patient 1 c.96dupC, patient 2 c.623G>A (p.G208D), patient 3 c.737G>A (p.Trp246*), patient 4 c.635G>C (p.Ser212Thr), patient 5 c.751_758del (p.Arg251Profs*47), patient 6 c.829-4C>G, and the same variant found in patients 7 and 8: c.584G>A (p. Arg195Gln). The fundoscopic findings are shown in the retinal images exams of the patients in the figure. The results are detailed on the table.
Conclusions :
Mutations of PRPH2 cause completely different clinical conditions and visual impairments. The study of this gene enables to combine together unrelated disease classifications. It would be easier to call it by "Spectrum of the PRPH2 gene Mutations", because several time it is difficult to classify an Inherited Retinal Disease in a patient who has PRPH2 gene pathogenic variants.
This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.