Clinical characteristics of recessive retinal degeneration due to mutations in the CDHR1 gene and a review of the literature

Background: The clinical phenotype of patients presenting with autosomal recessive CDHR1-related retinopathy has not been well described.

Materials and Methods: This is a retrospective case series of patients presenting to a single institution. Clinical data, including age, visual acuity, dilated fundus exam, fundus photos, fundus autofluorescence (FAF), optical coherence tomography, full-field electroretinograms (ERGs), and results of genetic testing, were collected.

Results: Four patients were identified to have biallelic mutations in the CDHR1 gene. All four patients were found to have at least one c.783G>A (p.Pro261 = ) mutation. A novel splice site mutation, c.152-2A>G, was identified in two patients. Patients became symptomatic between the fourth and sixth decades of life. Three patients presented initially with nyctalopia and peripheral visual field constriction, and one patient presented with simultaneous onset of photophobia and nyctalopia. The fundus appearance was characterized by macular atrophy with or without peripheral retinal pigment epithelium changes and arteriolar attenuation. FAF showed a hyperautofluorescent ring surrounding a central area of speckled hypoautofluorescence. Full-field electroretinography was available on three patients and showed decreased cone-and-rod responses.

Conclusions: CDHR1-related retinal dystrophy should be considered in adult patients with a retinal dystrophy who present with symptoms of cone-and-rod dysfunction and macular atrophy on ophthalmoscopic examination.