Phenotypic findings in C1QTNF5 retinopathy (late-onset retinal degeneration)

Abstract

Purpose: To describe the ocular and electrophysiological phenotype of four patients with late-onset retinal degeneration (LORD).

Methods: Clinical examination, fundus and anterior segment photography, fundus autofluorescence imaging and spectral domain optical coherence tomography (SD-OCT) were performed. Three patients underwent pattern and full-field electroretinography (ERG). Patient DNA was screened for the c.686C>G, p.Ser163Arg mutation in C1QTNF5.

Results: All affected individuals had a family history suggestive of autosomal dominant inheritance with full penetrance. Molecular analysis identified a heterozygous c.686C>G, p.Ser163Arg mutation in C1QTNF5 in DNA from all four affected probands. All four patients presented in their 50s with nyctalopia and developed central visual loss in their 60s. Peripupillary iris atrophy and long anterior zonular insertions were present in three of four patients. Dilated fundus examination revealed scalloped areas of retinal pigment epithelium (RPE) atrophy in the mid-periphery and widespread atrophy in the posterior pole. Full-field ERGs were consistent with rod-cone dystrophy with pattern ERG evidence of severe macular involvement. SD-OCT revealed widespread loss of the photoreceptors with absence of the inner/outer segment junction line and concurrent thinning of the outer nuclear layer. Diffuse choroidal thinning, mainly affecting the inner choroid with loss of the choriocapillaris, was observed.

Conclusion: C1QTNF5 retinopathy is an autosomal dominant LORD resulting in a complex ocular phenotype involving the RPE and ciliary epithelium. SD-OCT findings revealed widespread photoreceptor loss and diffuse choroidal thinning.