Sector Retinitis Pigmentosa and a Novel Rhodopsin Point Mutation—Case Series

Abstract

Purpose:

This article describes the clinical features and differential diagnosis of 4 cases of sector autosomal dominant (AD) retinitis pigmentosa (RP) studied with multimodal imaging, using autofluorescence (AF) imaging as a key diagnostic tool.

Methods:

The current study is an observational case series of 4 patients with characteristic visual field (VF) defects. Ophthalmic examination, VF testing, spectral-domain optical coherence tomography (SD-OCT), electrodiagnostic tests (EDTs), AF imaging, and genetic testing were performed in the 8 eyes of 4 patients (1 female and 3 male).

Results:

In all 4 cases, fundus examination revealed retinal pigment epithelial changes mainly in the inferotemporal retinal quadrant. The optic discs looked healthy, with no evidence of glaucomatous neuropathy. In each case, AF showed a bilateral, well-demarcated, leaf-like perivascular area of patchy hypoautofluorescence surrounded by a halo of hyperautofluorescence. SD-OCT over the leaf-like area confirmed that the interdigitation zone, ellipsoid zone, external limiting membrane, and outer nuclear layer were all affected. The EDT results varied among patients but confirmed involvement of both rods and cones in 1 patient. Genetic testing confirmed the diagnosis of AD-RP with a mutation in RHO c.491c>Tp.(Ala164Val) in all 3 male patients, and a new mutation c.66C>Ap.(Ser22Arg) in the female patient.

Conclusions:

AF is a fundamental diagnostic tool in both the diagnosis and follow-up of sector RP. We recommend that ophthalmologists perform AF as an adjunctive diagnostic test in cases of unexplained VF defects.