Familial exudative vitreoretinopathy caused by CTNNB1 gene de novo mutation in a Chinese family: a case report.

Background: Familial exudative vitreoretinopathy (FEVR) is an inherited disorder of retinal vascularization insufficiency caused primarily by genetic mutations. So far, FEVR has been less reported in the Chinese population. This study will provide a case of FEVR due to CTNNB1 splice mutation in a Chinese family, which will be helpful for genetic counseling and clinical diagnosis.

Methods: We collected a Chinese Han child with clinical manifestations of FEVR, accompanied by neurodevelopmental disorders. Whole exome sequencing (WES) showed the proband's CTNNB1 gene had a c.1060 + 1G > A de novo splicing mutation. Our analysis indicates that this variant produces a truncated protein that contributes to the development of the disease. Genetic testing confirmed the diagnosis of FEVR in proband from the study lineage. In addition, the proband also carries three novel gene mutation sites: the NIPBL gene c.3130G > A (p.Asp1044Asn), the CNGA1 gene c.568G > T (p.Glu190X), and the FBN2 gene c.5370A > G (p.Ile1790Met).

Conclusions: In this study, the c.1060 + 1G > A heterozygous mutation of the CTNNB1 gene is the main cause of FEVR disease in proband, and this pathogenic mutation expands the spectrum of CTNNB1 gene functional loss mutations in the Chinese population.