THE TARGET SIGN: A Near Infrared Feature and Multimodal Imaging in a Pluri-Ethnic Cohort with RDH5 -Related Fundus Albipunctatus

Purpose:Retinol dehydrogenase 5 (RDH5)-related fundus albipunctatus can present with phenotypic variability. Our purpose was to investigate new clinical characteristics and multimodal imaging findings in patients from different ethnic origins, carrying different mutations.Methods:Multicenter international retrospective case series of 18 patients with genetically confirmed RDH5-related fundus albipunctatus. Patients' files were reviewed for fundus images, visual acuity, macular optical coherence tomography scans, near-infrared images, fundus autofluorescence, electroretinogram, and genetic mutations. Imaging and electroretinogram findings.Results:All eyes (n = 36, 100%) showed small circular findings seen on near-infrared images, termed as the "target sign," correlating to the yellowish dots seen clinically and to the distinct hyperreflective linear lesions on optical coherence tomography at the level between external limiting membrane and retinal pigment epithelium. Perifoveal atrophy with foveal sparing was seen in 4 eyes of 2 patients (both RDH5 - c.160C>T, p.R54X mutation). Fundus autofluorescence revealed small hyperautofluorescent dots (n = 16, 44.4%). Scotopic electroretinograms were significantly reduced in all cases with an electronegative pattern, 66.7% displayed cone dysfunction.Conclusion:Our results show distinct imaging findings present in all patients with fundus albipunctatus independent of ethnicity or genetic mutation. Our results can facilitate the current algorithm to diagnose RDH5-related fundus albipunctatus and allow for targeted genetic testing.