Defects in the Cell Signaling Mediator ß-Catenin Cause the Retinal Vascular Condition FEVR.

Familial exudative vitreoretinopathy (FEVR) is an inherited blinding disorder characterized by the abnormal development of the retinal vasculature. The majority of mutations identified in FEVR are found within four genes that encode the receptor complex (FZD4, LRP5, and TSPAN12) and ligand (NDP) of a molecular pathway that controls angiogenesis, the Norrin-ß-catenin signaling pathway. However, half of all FEVR-affected case subjects do not harbor mutations in these genes, indicating that further mutated genes remain to be identified. Here we report the identification of mutations in CTNNB1, the gene encoding ß-catenin, as a cause of FEVR. We describe heterozygous mutations (c.2142_2157dup [p.His720∗] and c.2128C>T [p.Arg710Cys]) in two dominant FEVR-affected families and a de novo mutation (c.1434_1435insC [p.Glu479Argfs∗18]) in a simplex case subject. Previous studies have reported heterozygous de novo CTNNB1 mutations as a cause of syndromic intellectual disability (ID) and autism spectrum disorder, and somatic mutations are linked to many cancers. However, in this study we show that Mendelian inherited CTNNB1 mutations can cause non-syndromic FEVR and that FEVR can be a part of the syndromic ID phenotype, further establishing the role that ß-catenin signaling plays in the development of the retinal vasculature.

Novel mutations in the RS1 gene in Japanese patients with X-linked congenital retinoschisis.

X-linked congenital retinoschisis (XLRS) is an inherited retinal disorder characterized by reduced central vision and schisis of the macula and peripheral retina. XLRS is caused by mutations in the RS1 gene. We have identified 37 different mutations in the RS1 gene, including 12 novel mutations, in 67 Japanese patients from 56 XLRS families. We present clinical features of these patients in relation to the associated mutations.