Cone dystrophy with supernormal rod responses: A rare KCNV2 gene variant

• Type: Article in International Scientific Journal
• Date: 2021

Authors

Esteves Leandro, J (Author) Other; Torres Costa, S (Author) Other; Estrela Silva, S (Author) Other; Santos Silva, R (Author) FMUP; Brandão, E (Author) Other; Grangeia, A (Author) Other; Fernandes, S (Author) Other; Oliveira, R (Author) Other; Falcão Reis, F (Author) Other; Rocha-Sousa A (Author) FMUP

Journal

Title: European Journal of Ophthalmology

ISSN: 1120-6721

Publisher: WICHTIG PUBLISHING

Indexing

Scopus - 1 Citation

Other information

Authenticus ID: P-00T-NK1

DOI: 10.1177/11206721211000000

Abstract (EN): Purpose: To describe the clinical, electrophysiological, and genetic findings of three Portuguese families with a rare variant in the KCNV2 gene resulting in ¿cone dystrophy with supernormal rod responses¿ (CDSRR). Methods: Retrospective clinical revision of five individuals from three unrelated families with CDSRR. Ophthalmological examination was described in all patients and included color vision testing, fundus photography, fundus autofluorescence (FAF) imaging, spectral domain-optical coherence tomography (SD-OCT), pattern electroretinogram (ERG), and full-field ERG. The mutational screening of the KCNV2 gene was performed with Sanger and Next Generation Sequencing. Results: All patients showed childhood-onset photophobia and progressive visual acuity loss with varying degrees of severity. In multimodal imaging, various degrees of retinal pigment epithelium disturbances and outer retinal atrophy, which tend to be worst with advancing age, were observed. Molecular screening identified a rare presumed truncating variant (p.Glu209Ter) in homozygosity in two families and in compound heterozygosity in a third family. Three patients showed ERG changes characteristic of CDSRR, however, two patients presented with incomplete electrophysiological features of the disease. Conclusion: A rare variant in the KCNV2 gene was identified in five patients from three Portuguese families. This variant often leads to a severe and progressive form of retinopathy. Considerable variability in the ERG responses among patients with this KCNV2 variant was observed. © The Author(s) 2021.

Language: English

Type (Professor's evaluation): Scientific