|ZFIN ID: ZDB-PUB-130708-16|
|Source:||Proceedings of the National Academy of Sciences of the United States of America 110(24): 9856-9861 (Journal)|
|Registered Authors:||Dona, Margo|
|PubMed:||23716654 Full text @ Proc. Natl. Acad. Sci. USA|
Familial exudative vitreoretinopathy (FEVR) is a genetically heterogeneous disorder characterized by abnormal vascularization of the peripheral retina, which can result in retinal detachment and severe visual impairment. In a large Dutch FEVR family, we performed linkage analysis, exome sequencing, and segregation analysis of DNA variants. We identified putative disease-causing DNA variants in proline-alanine-rich ste20-related kinase (c.791dup; p.Ser265ValfsX64) and zinc finger protein 408 (ZNF408) (c.1363C>T; p.His455Tyr), the latter of which was also present in an additional Dutch FEVR family that subsequently appeared to share a common ancestor with the original family. Sequence analysis of ZNF408 in 132 additional individuals with FEVR revealed another potentially pathogenic missense variant, p.Ser126Asn, in a Japanese family. Immunolocalization studies in COS-1 cells transfected with constructs encoding the WT and mutant ZNF408 proteins, revealed that the WT and the p.Ser126Asn mutant protein show complete nuclear localization, whereas the p.His455Tyr mutant protein was localized almost exclusively in the cytoplasm. Moreover, in a cotransfection assay, the p.His455Tyr mutant protein retains the WT ZNF408 protein in the cytoplasm, suggesting that this mutation acts in a dominant-negative fashion. Finally, morpholino-induced knockdown of znf408 in zebrafish revealed defects in developing retinal and trunk vasculature, that could be rescued by coinjection of RNA encoding human WT ZNF408 but not p.His455Tyr mutant ZNF408. Together, our data strongly suggest that mutant ZNF408 results in abnormal retinal vasculogenesis in humans and is associated with FEVR.
Familial exudative vitreoretinopathy (FEVR) is a well-characterized developmental anomaly of the retinal vasculature that was first described by Criswick and Schepens in 1969. The most prominent characteristics of the disease result from the incomplete and aberrant vascularization of the peripheral retina and/or retinal blood vessel differentiation. The latter can lead to various complications, such as retinal neovascularization and exudates, vitreous hemorrhage, vitreoretinal traction, ectopia of the macula, and retinal folds and detachments (3). The clinical signs in affected individuals can be diverse, ranging from hardly detectable vascular anomalies in the peripheral retina in asymptomatic individuals to bilateral retinal detachments leading to blindness.
FEVR displays all Mendelian forms of inheritance. To date, mutations in genes encoding frizzled 4 (FZD4), low-density lipoprotein receptor-related protein 5 (LRP5), tetraspanin-12 (TSPAN12), and Norrin [encoded by Norrie Disease Pseudoglioma (NDP)] have been shown to cause FEVR. The proteins encoded by these genes participate in the norrin/β-catenin pathway, in which LRP5 and FZD4 act as coreceptors, NDP as a ligand for FZD4 and TSPAN12 as an aid for FZD4 multimerization. Mutations in these genes explain up to <50% of all reported FEVR cases.
We previously excluded mutations in FZD4, LRP5, and TSPAN12 in 10 Dutch probands with adFEVR. In the largest genetically unsolved adFEVR family, linkage analysis was combined with an unbiased exome sequencing approach of two distantly related relatives, leading to identification of a missense mutation in zinc finger protein 408 (ZNF408) as a novel cause of autosomal dominant (ad) FEVR. Cellular transfection studies suggest a dominant-negative disease mechanism, and morpholino (MO)-induced knockdown of znf408 in zebrafish show its involvement in development of the retinal vasculature.