Rod-Cone Dystrophy with Initially Preserved Visual Acuity Despite Early Macular Involvement Suggests Recessive CERKL Mutations

Purpose: To highlight that recessive CERKL mutations cause an early-onset rod-cone dystrophy with initially preserved visual acuity despite early macular involvement, an unusual and distinct initial phenotypic presentation.

Methods: A retrospective case series.

Results: Two young Saudi Arabian adults complained of worsening night blindness over the preceding few years, one of whom had been symptomatic since early childhood. Both had retinal pigment epithelium (RPE) mottling/granularity, vascular attenuation, few bone spicules, and frank macular RPE atrophic changes despite relatively preserved visual acuity. Electroretinography was non-recordable, and ocular coherence tomography confirmed retinal thinning, particularly of the outer nuclear layer in the fovea. Each patient harbored a different homozygous CERKL mutation (p.L245P, p.C333*). The few prior reports that detail the presenting phenotype of CERKL mutations describe children or young adults with the similar unusual presenting constellation of findings: rod-cone dystrophy and frank macular atrophy but relatively preserved visual acuity. With time, central vision is affected.

Conclusions: The initial presenting features of CERKL-related retinopathy are distinct and unusual. Recognition of this initial presenting phenotype can facilitate earlier molecular diagnosis and genetic counseling.