Seven Novel and Three Known Mutations in FOXL2 in 10 Chinese Families with Blepharophimosis Syndrome

Background: Blepharophimosis syndrome (BPES) is characterized by eyelid malformation with occasional premature ovarian failure. Mutations in FOXL2 underlie a fraction of BPES cases. Objective: We aimed to investigate the genetic basis of BPES in 26 Chinese families that included 78 patients. Methods: We performed ophthalmological examinations on each family member. We used Sanger sequencing to screen FOXL2 exons and their flanking sequences. We also performed bioinformatics studies, structural modeling and pathogenicity evaluations on all identified variations. Literature was reviewed and genotype-phenotype correlation analysis was performed. Results: The patients had typical manifestations of BPES. Ten mutations were identified in ten of the twenty-six families. Among these, seven were novel mutations. These included the six truncating mutations, p.Glu69*, p.Gly256Glyfs*14, p.Ala14Serfs*135, p.Pro333Profs*200, p.Pro290Leufs*70, and p.Pro157Profs*91, and one missense mutation, p.Tyr59Cys. The mutations were scattered within the gene, and no mutational hotspots were found. Genotype-phenotype correlation analysis showed that frameshift or nonsense mutations were correlated with type I BPES, while in-frame or missense mutations were associated with type II BPES. Conclusion: We report the largest BPES cohort in China thus far as well as seven novel mutations in FOXL2. The identification of novel mutations has not only expanded the mutational spectrum of the gene (which is valuable for mutation detection-based screening) but also suggests that most mutations within the Chinese population may not have been characterized yet.