Severe Familial Exudative Vitreoretinopathy, Congenital Hearing Loss, and Developmental Delay in a Child With Biallelic Variants in FZD4.
JAMA Ophthalmol 2022;
140:889-893. [PMID:
35951321 PMCID:
PMC9372905 DOI:
10.1001/jamaophthalmol.2022.2914]
[Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022]
Abstract
Question
Are FZD4 variants associated with familial exudative vitreoretinopathy (FEVR) with extraocular features?
Findings
This case series included a patient with biallelic FZD4 variants with severe FEVR in infancy, congenital hearing loss, and developmental delay. Each parent was carrying 1 of the alleles and manifested mild FEVR; cell-based FZD4 receptor-activation assays determined that FZD4 function was dramatically decreased in the presence of these compound heterozygous variants.
Meaning
Biallelic variants in FZD4 can result in a severe ocular phenotype with systemic features, which may represent a novel syndrome.
Importance
Familial exudative vitreoretinopathy (FEVR) is a nonsyndromic autosomal dominant retinal disorder commonly caused by variants in the FZD4 gene. This study investigates the potential role beyond ocular abnormalities for FZD4 gene variants in patients with FEVR.
Objective
To evaluate the role of FZD4 in symptoms beyond those associated with FEVR through a patient with biallelic variants in FZD4.
Design, Setting, and Participants
This case series included the DNA testing and phenotyping of 1 patient proband and her parents, combined with signaling assays, to determine the association of patient-derived compound heterozygous variants on FZD4 signaling and biologic function.
Main Outcomes and Measures
FZD4 genes were tested using next-generation sequencing and Sanger sequencing. Cell-based assays measured the effect of the variants on FZD4 signaling.
Results
The proband presented with absent red reflexes from complete tractional retinal detachments diagnosed at 3 days of age and failed the newborn screening hearing test. Auditory brainstem response at 6 months of age showed bilateral mild to moderate high-frequency sensorineural hearing loss. The patient manifested developmental delays in speech and walking. Intravenous fluorescein angiography (IVFA) of the patient’s parents detected stage 1 FEVR. Genetic testing revealed 2 FZD4 variants in the patient, each variant found in 1 parent. Signaling assays confirmed that the presence of both variants was associated with significantly worse signaling activity compared with the heterozygous state.
Conclusions and Relevance
Results of this case series suggest that extraocular syndromic FEVR was associated with FZD4 variants. The decrease in FZD4 signaling owing to the biallelic nature of the disease resulted in hearing deficits, developmental delays, and a more severe retinal phenotype.
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