Confirmation of PRDX3 c.568G>C as the Genetic Basis of Punctiform and Polychromatic Pre-Descemet Corneal Dystrophy

Abstract

The aim of this study was to report the results of screening peroxiredoxin 3 (PRDX3) and PDZ domain-containing protein 8 (PDZD8) in a previously unreported pedigree with punctiform and polychromatic pre-Descemet corneal dystrophy (PPPCD) to confirm that the PRDX3 mutation c.568G.C is the genetic basis of PPPCD.Methods: Ophthalmologic examination of the proband and her affected father was performed with slit lamp biomicroscopy. Saliva was collected from the proband as a source of DNA, after which screening for PRDX3 and PDZD8 was performed.Results: Slit lamp examination of the proband revealed polychromatic deposits diffusely distributed at the pre-Descemet level in both corneas and anterior subcapsular in the crystalline lens of both eyes. The proband's father also demonstrated diffuse pre-Descemetic polychromatic deposits in both eyes but no lenticular deposits. Screening of PRDX3 in the proband demonstrated the c.568G.C (p.Asp190His) variant previously associated with PPPCD and failed to identify any variants in PDZD8. Conclusions:We report the initial confirmation of PRDX3 as the genetic basis of PPPCD in a previously unreported pedigree and expand the phenotype of PPPCD to include polychromatic lenticular deposits.

IC3D Classification of Corneal Dystrophies—Edition 3

“…In 2020, PPPCD was mapped to the PRDX3 gene on chromosome 10. 20 The pre-Descemet opacities in PPPCD are polychromatic, larger, and more punctate than those in the degeneration, cornea farinata. We have chosen to include PPPCD within the PDCDs template so that clinicians can easily compare the findings of PPPCD, with which they may be unfamiliar, with the more common degenerative condition of cornea farinata.…”

“…In addition, a single patient with PPPCD was found to also have polychromatic crystals beneath their lens capsule, introducing the question of whether PPPCD is actually a corneal dystrophy or a manifestation of a systemic disease. 20…”

Monogenic Disorders of ROS Production and the Primary Anti-Oxidative Defense

“…The phenotype, which was not reported in patients with homozygous pathogenic PRDX3 variants, is characterized by hyperreflective deposits in the posterior stroma of the cornea of the eye. Affected individuals are asymptomatic with no visual impairment [119][120][121].…”