ObjectiveTo observe and investigate the related factors that might affect clinical features of familial exudative vitreoretinopaty (FEVR) patients. MethodsA retrospective chart study. From January 2012 and December 2021, 42 patients with 84 eyes with a diagnosis of FEVR from Department of Ophthalmology, Peking University People's Hospital were included in the study. The patients came from 42 separate families. There were 31 males and 11 females, with an average age of first diagnosis was 16.6±33.7 months. There were 21 patients referred from other hospitals for the fundus disease found in eye screening after birth, 21 patients were first seen in our hospital. There were 4 and 38 premature and full-term infants, respectively. Two patients with a positive family history of FEVR. All patients are FEVR stages 1-5. The wide-angle digital pediatric retinal imaging system after general anesthesia for fluorescein fundus angiography (FFA) examination were performed for patients aged ＜5 years. If patients ≥ 5 years old, routine FFA examination was performed. Sixty-eight first-degree relatives from 28 families undergo routine fundus examinations and FFA examination. Genetic examination was performed for 26 families, including 26 probands and 57 first-degree relatives. Genetic examination were performed on gene the coreceptor of low density lipoprotein receptor-associated protein 5 (LRP5), Wnt receptor coiled protein 4 (FZD4), Norrie disease (NDP), tetraporin 12 (TSPAN12), catenin β1 (CTNNB1) genes known to be involved in FEVR. The clinical features and the genotype of FEVR were observed in relation to the clinical phenotype. ResultsAmong the 42 patients, 13 patients were first observed by strabismus and nystagmus, with the median age of 12 months. Eight patients were complained non-chasing or vision-related symptoms. Among the 84 eyes, FEVR stage 1 or 2, 3 or 4, and 5 were 50 (59.5%, 50/84), 31 (36.9%, 31/84), and 3 (3.6%, 3/84) eyes, respectively. Among the 23 patients who were > 3 months at first diagnosis, 16 patients had at least one eye severer than stage 3 (69.6%, 16/23). Of the 68 first-degree relatives, 22 (32.4%, 22/68) had FEVR-like changes. Among the 26 families that underwent genetic detection, 13 families (50%, 13/26) of 16 variants of FEVR-related genes were detected, of which 10 mutations of LRP5 gene were the most common. There were 10 families with single gene mutations, including 6, 2 and 2 families of LRP5, FZD4 and CTNNB1 genes, respectively. One family of LRP5 gene mutations were compound heterozygous mutations, 1 family with LRP5 gene mutaition combined with NDP gene mutation, and 1 family with LRP5 and TSPAN12 gene mutation. Among the proband with FEVR pathogenic genes, 6 cases with similiar stage of both eyes, and 7 cases with inconsistent disease stages, and there was no obvious correlation between gene mutations and clinical phenotypes. ConclusionIn addition to the age of first diagnosis, no exact factors affecting the clinical manifestations of FEVR are found, and the association between clinical phenotypic and genetic heterogeneity still needs to be further explored.