A Novel Frameshift Variant in KIF11 Causes Autosomal Dominant Familial Exudative Vitreoretinopathy in a Chinese Family

Background: Familial exudative vitreoretinopathy (FEVR) is a rare inherited ocular disorder characterized by abnormal peripheral retinal vascular development. KIF11 variants are known to cause autosomal dominant FEVR, but novel pathogenic variants remain to be identified. Objective: This study aimed to identify a novel causative variant of FEVR and provide evidence for genetic counseling. Methods: Whole-exome sequencing was performed on members of a Chinese family with FEVR. Rare variants with a gnomAD allele frequency <0.1% in East Asian and general populations were prioritized. Sanger sequencing was used for validation, and bioinformatic analyses (including Combined Annotation Dependent Depletion [CADD] score and cross-species conservation analysis) were conducted to assess pathogenicity. Results: A novel heterozygous frameshift variant KIF11 c.1239_1240del (p.V414Sfs*9) was identified in the proband, his brother, and his mother. This variant, absent from public databases (1000 Genomes, ExAC, gnomAD), had a CADD score of 26.9 and affected a highly conserved residue, suggesting disruptive effects on protein structure. The proband’s mother showed macular involvement. Conclusions: The novel KIF11 frameshift variant (c.1239_1240del p.V414Sfs*9) identified in a Chinese family expands the mutation spectrum of autosomal dominant FEVR, with macular involvement aiding clinical prognostic assessment.