Clinical presentation and genetic correlation of patients with mutations affecting the FZD4 gene

Abstract

Objective: To correlate the ophthalmic findings of patients with pediatric vitreoretinopathies with mutations occurring in the FZD4 gene.

Methods: A total of 123 patients diagnosed with autosomal-dominant familial exudative vitreoretinopathy (AdFEVR) or retinopathy of prematurity (ROP) and 42 control patients were enrolled in the study. Diagnoses were based on retinal findings at each patient's first examination or during ROP screening. Genomic DNA was isolated and polymerase chain reaction and direct sequencing of the FZD4 gene performed.

Results: FZD4 gene mutations were discovered in 13 of the 123 (10.6%) patients. Nine of the 63 patients with AdFEVR (14.3%) has mutations in the FZD4 gene. Four heterozygous mutations were identified: C117R, C181Y, Q505X, and P33S/P168S. Four of the 60 patients with ROP (6.7%) have a double missense mutation P33S/P168S that was also found in the patients with FEVR. No other FZD4 mutations were found in the patients with ROP. Additionally, patients expressing the double mutation had clinical presentations that overlapped, making it difficult to assign a definitive diagnosis. None of the mutations found in the patients with FEVR or ROP were seen in the control chromosomes.

Conclusion: Mutations occurring in the FZD4 gene affect patients diagnosed with both FEVR and ROP. The clinical picture often overlaps and may require a detailed birth and family history for diagnosis. Genetic testing confirms inherited vitreoretinopathy and helps direct clinical management. Clinical Relevance Patients diagnosed with ROP may have a mutation in the FZD4 gene and display characteristics consistent with FEVR. Analysis of the FZD4 gene should be considered.