The first deaf-blind patient in Russia with Argus II retinal prosthesis system: what he sees and why.

OBJECTIVE: In this study, we propose a new method for evaluating the functional results based on the sizes of phosphenes that the patient drew which were then digitalized. We also describe the methodology of psychological testing and support for a deaf-blind patient. APPROACH: A 59-year-old man with retinitis pigmentosa and hearing loss (clinical Usher syndrome) underwent surgery to implant the Argus II retinal prosthesis system in his right eye. MAIN RESULTS: Correlation analysis showed a weak dependency between the size of a phosphene and the perceptual threshold. Significant correlations between a phosphene and the height of the interface, impedance or retinal thickness was not found. The patient with the retinal prosthesis felt more independent and confident, and more healthy. This is the first case of retinal implant surgery in Russia. SIGNIFICANCE: The results of this study add to the understanding in the field of retinal implants functioning. The experience of the successful rehabilitation of the deaf-blind patient after implantation of Argus II allowed us to design a methodology that can be used in future similar cases.

Genetic screening of Russian Usher syndrome patients toward selection for gene therapy.

BACKGROUND: Usher syndrome (USH) is heterogeneous in nature and requires genetic test for diagnosis and management. Mutations in USH associated genes are reported in some populations except Russians. Here, we first time represented the mutation spectrum of a Russian USH cohort. METHODS: Twenty-eight patients with USH were selected from 3214 patients from Deaf-Blind Support Foundation "Con-nection" during 2014-2016 following the observational study NCT03319524. Complete ophthalmologic, ENT, and vestibular medical tests were done for clinical characterization. NGS, MLPA, and Sanger sequencing were considered for genetic analysis. RESULTS: Around 53.57% and 39.28% patients had USH1 and USH2, respectively; 17.85% cases (n = 5/28) had no known mutation. Eleven (73.33%) subjects showed variations in USH1 associated genes MYO7A (72.72%), CDH23 (9.09%), PCDH15 (9.09%), and USH1C (9.09%). Eleven mutations are detected in MYO7A where 54.54% are novel. MYO7A: p.Q18* was most frequent (27.27%) mutation and is associated with early manifestation and most severe clinical picture. Two novel mutations (p.E1301* and c.158-?_318+?del) are detected in PCDH15 gene. Around 90.90% patients suspected to be USH2 are confirmed by genetic testing. Eleven mutations detected in the USH2A gene, where 27.27% were novel. Most common USH2A mutation is p.W3955* (50%) followed by p.E767fs, p.R1653*, and c.8682-9A> G (20% each). CONCLUSION: The Russian USH cohort shows both novel and known USH mutations. Clinically the prevalence of USH2 is low (39.28%) and the frequency of MYO7A mutations responsible for USH1B is very high (63.63%, N = 7/11) compared to other cohorts. These seven patients carrying MYO7A mutations are preliminarily eligible for the UshStat® gene therapy.