Is exon 8 the most critical or the only dispensable exon of the VCAN gene? Insights into VCAN variants and clinical spectrum of Wagner syndrome

Wagner syndrome and erosive vitreoretinopathy together constitute the phenotypic continuum of an autosomal dominant vitreoretinopathy, with clinical findings typically isolated to the eye. The disease is caused by pathogenic variants in the VCAN gene and all such variants reported to date are those that plausibly result in haploinsufficiency of exon 8 containing vcan transcripts. Here, we report the molecular findings and long-term follow-up of a 16-year-old female with a history of retinal detachments and pigmentary retinal changes. Next-generation sequencing and microarray analysis of 141 genes established a diagnosis of Wagner syndrome in this individual, by detection of an 11.7 kilobase (kb) deletion encompassing exon 8 of VCAN. In light of the emerging functions and roles of versican protein in human disease, we discuss how variants within exon 8 of the VCAN gene can be compared to those in exon 2 of the COL2A1 gene that cause atypical Stickler syndrome and propose that variants in other regions of the gene can be expected to present with a more systemic disease. The distinctive facial features and atypical gastrointestinal symptoms observed in this long-term follow-up study support the possibility that individuals with VCAN-related vitreoretinopathy may have extra-ocular clinical features.