Clinical and Genetic Findings in Korean Patients with Choroideremia.

Abstract

We share and analyze the clinical presentations and genotypes of Korean male patients and female carriers who visited our clinic. Six male patients and three female carriers with comprehensive ophthalmic examinations and next-generation sequencing were included. Detailed clinical features were identified using visual field (VF) test and multimodal imaging including color fundus photography, fundus autofluorescence (FAF), optical coherence tomography (OCT). Six male patients were diagnosed with choroideremia at the median age of 25 years. Before genetic testing, three (50.0%) patients were clinically diagnosed with choroideremia, while the other three (50.0%) patients with retinitis pigmentosa (RP). Patients showed different types of hemizygous CHM mutation, including two nonsense mutations (c.715C>T, p.Arg239Ter; c.799C>T, p.Arg267Ter), two frameshift mutations (c.1584_1587del, p.Val529HisfsTer7; c.403_404delGA, p.Asp135PhefsTer9), one splicing mutation (c.1511-28_1511-2del), and one exon duplication (2-9). The latter three mutations are novel findings. Two female carriers showed exon duplication (2-9) and the other one female carrier showed nonsense mutations (c.715C>T, p.Arg239Ter) in heterozygote form. Fundus showed diffuse yellow-whitish scleral reflex and granular pigmented lesions. FAF showed multiple patchy hypofluorescence lesions, sparing macula. OCT showed thinning of outer nuclear layer, ellipsoid zone, RPE layer, choroid thickness, interlaminar bridges (ILBs), outer retinal tubulations (ORTs), and microcysts in the inner nuclear layer. VF showed ring scotoma pattern with small amount of remaining central field. Asymptomatic female carriers showed variable fundus findings and mild changes in OCT. A detailed description of the genotypes with three novel mutations and phenotypes of six choroideremia patients and three CHM mutation female carriers are presented.