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Inherited retinal disease (IRD) is clinically and genetically heterogeneous. Awareness of the importance of genetic testing for IRD in the clinical setting is increasing with the recent development of new therapeutic strategies, such as gene therapy. Here, the perception of genetic testing, including its benefits and potential challenges, among patients with IRD was investigated to establish strategies for IRD genetic testing and counseling practices that can meet the requirements of the patients in Japan. An anonymous self-administered questionnaire was distributed to 275 patients with IRD who underwent genetic testing after clinical consultation and genetic counseling to investigate the motivations for genetic testing, benefits, challenges, status of communication of results to family, and attitude to timing of genetic testing. In total, 228 (82.9%) responses were analyzed. Several major motivations for genetic testing were identified, including gaining information on future treatment options and clarification of the inheritance pattern, among others. No association was found between the sharing of results with family members and the results of genetic testing. Moreover, according to patients who received positive results, the benefits of genetic testing included information on the inheritance pattern, additional information on the diagnosis, and mental preparation for the future. Even patients who received negative or inconclusive (variant of uncertain significance) results reported certain informative and psychological benefits. Altogether, these findings suggest that provisions for genetic testing and genetic counseling are necessary within a certain period after clinical diagnosis and it is necessary to facilitate appropriate family communication about genetic testing results while paying attention to the background of family relationships. Moreover, the benefits of genetic testing can be influenced by the careful interpretation and information provided on the test results during genetic counseling and consultation., (© 2022 National Society of Genetic Counselors.)

Background: Little is known about genotype–phenotype correlations of RP1-associated retinal dystrophies in the Japanese population. We aimed to investigate the genetic spectrum of RP1 variants and provide a detailed description of the clinical findings in Japanese patients. Methods: In total, 607 patients with inherited retinal diseases were examined using whole-exome/whole-genome sequencing (WES/WGS). PCR-based screening for an Alu element insertion (c.4052_4053ins328/p.Tyr1352AlafsTer9) was performed in 18 patients with autosomal-recessive (AR)-retinitis pigmentosa (RP) or AR-cone dystrophy (COD)/cone-rod dystrophy (CORD), including seven patients with heterozygous RP1 variants identified by WES/WGS analysis, and 11 early onset AR-RP patients, in whom no pathogenic variant was identified. We clinically examined 25 patients (23 families) with pathogenic RP1 variants, including five patients (five families) with autosomal-dominant (AD)-RP, 13 patients (11 families) with AR-RP, and seven patients (seven families) with AR-COD/CORD. Results: We identified 18 pathogenic RP1 variants, including seven novel variants. Interestingly, the Alu element insertion was the most frequent variant (32.0%, 16/50 alleles). The clinical findings revealed that the age at onset and disease progression occurred significantly earlier and faster in AR-RP patients compared to AD-RP or AR-COD/CORD patients. Conclusions: Our results suggest a genotype–phenotype correlation between variant types/locations and phenotypes (AD-RP, AR-RP, and AR-COD/CORD), and the Alu element insertion was the most major variant in Japanese patients with RP1-associated retinal dystrophies. [ABSTRACT FROM AUTHOR]