Familial exudative vitreoretinopathy (FEVR) is a disease exhibits a wide range of clinical signs, ranging mild peripheral retinal vascular anomalies to severe retinal detachments. Individuals with mild FEVR are frequently asymptomatic with good visual function and are often undiagnosed. However, little is known about the genetic characters of the cohort. The purpose of this study was to investigate the clinical characteristics and genetic spectrum of in patients with asymptomatic mild FEVR. Herein, sixty-two patients (124 eyes) with asymptomatic mild FEVR were studied in a case series. Comprehensive ophthalmic examinations and genetic testing were performed in all patients. Clinical examinations showed that the avascular zone was seen in all 124 eyes and was the most common abnormality observed. Increased vessel branching and straightened peripheral vessel branches were found in 122 (98.4%) eyes. Late-phase angiographic posterior and peripheral leakage (LAPPEL) was observed in 80 (64.5%) eyes and V-shape degeneration was noted in 36 (29.0%) eyes. Other manifestations including extensive anastomoses, retinal ridges, and extraretinal neovascularization, which were detected in 30 (24.2%), 10 (8.1%) and 2 (1.6%) eyes respectively. Overall, pathogenic mutations were identified in 48.4% (30/62) of individuals with asymptomatic mild FEVR. Mutations in FZD4, LRP5, TSPAN12, and KIF11 were detected in 21.0% (13/62), 12.9% (8/62), 12.9% (8/62), and 1.6% (1/62) of our patients respectively. Ten novel mutations were found. In conclusion: Pathogenic mutations in the known FEVR-associated genes were detected in nearly half (48.4%) of the asymptomatic mild FEVR cohort. Among these mutations, FZD4 was predominant, appearing in 21.0% of all individuals. Patients with asymptomatic mild FEVR should receive timely examinations, lifelong monitoring, and some of them need preventive therapy and treatment. Additionally, we discovered 10 novel variants, which may enable a deeper understanding of this disease.

中文翻译：

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无症状轻度家族性渗出性玻璃体视网膜病变患者的基因突变谱。

家族性渗出性玻璃体视网膜病变（FEVR）是一种表现出广泛临床症状的疾病，其范围从轻度的周边视网膜血管异常到严重的视网膜脱离。轻度FEVR的个体通常无症状，视觉功能良好，并且常常未被诊断。但是，对该人群的遗传特征知之甚少。这项研究的目的是调查无症状轻度FEVR患者的临床特征和遗传谱。在此，对一个病例系列中的62例无症状轻度FEVR患者（124眼）进行了研究。所有患者均进行了全面的眼科检查和基因检测。临床检查表明，在所有124眼中都可见到无血管区，这是观察到的最常见的异常。在122（98.4％）眼中发现增加的血管分支和伸直的周围血管分支。在80（64.5％）眼中观察到后期血管造影的前后及周围渗漏（LAPPEL），并且在36（29.0％）眼中发现了V型变性。其他表现包括广泛的吻合，视网膜脊和视网膜外新生血管形成，分别在30眼（24.2％），10眼（8.1％）和2眼（1.6％）检出。总体而言，在无症状轻度FEVR的个体中发现了48.4％（30/62）的致病突变。在我们的患者中分别检测到FZD4，LRP5，TSPAN12和KIF11的突变为21.0％（13/62），12.9％（8/62），12.9％（8/62）和1.6％（1/62）。发现了十个新颖的突变。结论：在近一半的已知FEVR相关基因中发现了致病突变（48。4％的无症状轻度FEVR队列。在这些突变中，以FZD4为主，占所有个体的21.0％。无症状轻度FEVR的患者应及时检查，终生监测，其中一些需要预防性治疗。此外，我们发现了10种新颖的变异，可以使人们对该病有更深入的了解。