Familial Exudative Vitreoretinopathy and Systemic Abnormalities in Patients With CTNNB1 Mutations

Vitreoretinopathy in Asymptomatic Children With CTNNB1 Syndrome

Importance

Previous studies have identified familial exudative vitreoretinonpathy (FEVR) in patients with CTNNB1 syndrome based on severe congenital ocular phenotypes. However, ophthalmoscopy may not be sufficient to detect vision-threatening vitreoretinopathy in all patients.

Objective

To report a consecutive retrospective case series of 11 patients with CTNNB1 variants who had previously unremarkable ophthalmoscopic examination results and to describe their detailed ophthalmic phenotypes.

Design, Setting, and Participants

This retrospective case series was conducted at the Children's Hospital of Philadelphia from October 2022 to November 2023 among patients with identified variants in CTNNB1 and previously documented normal results in office retinal examinations. These consecutive patients subsequently underwent an examination under anesthesia with fluorescein angiography. Detailed genotype information was analyzed for all patients, and each variant was mapped on the CTNNB1 gene to observe any associations with severity of vitreoretinopathy.

Main Outcomes and Measures

Number of patients with vitreoretinopathy and number requiring treatment for vitreoretinopathy.

Results

The mean (SD) age at the time of CTNNB1 syndrome diagnosis was 2 (1) years, and the mean (SD) age at examination was 6 (3) years for the 11 total patients. A total of 9 patients had a diagnosis of strabismus, and 5 patients had undergone strabismus surgery. FEVR was present in 5 of 11 patients and in 9 eyes. The presence of disease requiring treatment was identified in 6 eyes, including 1 retinal detachment. Detailed genotype analysis of the patients found no clearly delineated high-risk loci in CTNNB1 in association with high severity of FEVR.

Conclusions and Relevance

In this case series study, nearly all patients with CTNNB1 syndrome required ophthalmic care for refractive error and strabismus, and a subset also required treatment for FEVR. These findings support consideration of ultra-widefield fluorescein angiography among individuals with CTNNB1 syndrome when feasible, including the use of sedation if such an assessment is not possible in the office setting.

De novel heterozygous copy number deletion on 7q31.31-7q31.32 involving TSPAN12 gene with familial exudative vitreoretinopathy in a Chinese family

AIM

To investigate the genetic and clinical characteristics of patients with a large heterozygous copy number deletion on 7q31.31-7q31.32.

METHODS

A family with familial exudative vitreoretinopathy (FEVR) phenotype was included in the study. Whole-exome sequencing (WES) was initially used to locate copy number variations (CNVs) on 7q31.31-31.32, but failed to detect the precise breakpoint. The long-read sequencing, Oxford Nanopore sequencing Technology (ONT) was used to get the accurate breakpoint which is verified by quantitative real-time polymerase chain reaction (QPCR) and Sanger Sequencing.

RESULTS

The proband, along with her father and younger brother, were found to have a heterozygous 4.5 Mb CNV deletion located on 7q31.31-31.32, which included the FEVR-related gene TSPAN12. The specific deletion was confirmed as del(7)(q31.31q31.32)chr7:g.119451239_123956818del. The proband exhibited a phase 2A FEVR phenotype, characterized by a falciform retinal fold, macular dragging, and peripheral neovascularization with leaking of fluorescence. These symptoms led to a significant decrease in visual acuity in both eyes. On the other hand, the affected father and younger brother showed a milder phenotype.

CONCLUSION

The heterozygous CNV deletion located on 7q31.31-7q31.32 is associated with the FEVR phenotype. The use of long-read sequencing techniques is essential for accurate molecular diagnosis of genetic disorders.