Prevalence and genetic–phenotypic characteristics of patients with USH2A mutations in a large cohort of Chinese patients with inherited retinal disease

AIMS: To investigate the frequency of USH2A mutation and the clinical and genetic differences between Usher syndrome type II (USH2) and retinitis pigmentosa (RP) in a large cohort of Chinese patients. METHODS: A total of 1381 patients with inherited retinal disease (IRD) were recruited. The phenotypic and genotypic information of patients with USH2A mutations was evaluated. RESULTS: The prevalence of patients with USH2A mutations was 15.75%, which was the most frequently detected gene in this cohort of patients. Hotspot of USH2A mutations was c.8559-2A >G and c.2802T >G. Patients with USH2 had an earlier and more serious decline of visual function and damage to retina structure than did patients with RP in the first 10 years (p<0.05), but there was no difference in the visual prognosis between the two groups when the course of disease exceeded 10 years (p>0.05). Missense variants had less severe consequences and were found more commonly in RP, whereas more deleterious genotypes were associated with an earlier onset of disease and were found more commonly in USH2. CONCLUSIONS: This study provides detailed clinical–genetic assessment of patients with USH2A mutations of Chinese origin, enabling precise genetic diagnoses, better management of these patients and putative therapeutic approaches.