Further evidence that a specific homozygous CLDN19 variant results in non-syndromic maculopathy and can be mistaken for prior ocular toxoplasmosis infection

Introduction: Round atrophic macular scars with a hyperpigmented rim in an otherwise healthy child are characteristic for prior ocular toxoplasmosis infection, the most common etiology of self-resolved retinitis in immunocompetent patients. However, a specific homozygous gene mutation (NM_148960: CLDN19: c. 263T>A; p.Val88Glu) can result in a similar phenotype.

Methods: Retrospective case series (2018-2023) of children homozygous for the gene mutation CLDN19: c. 263T>A; p.Val88Glu. Five children (3 families) were identified.

Results: All 5 identified affected children had been referred for reduced vision and had bilateral central macular scars. Three children (2 families) were originally diagnosed with presumed prior ocular toxoplasmosis infection. All 5 children have stable ophthalmic finding over 5-6 years of follow-up. Although other CLDN19 mutations are associated with early-onset pediatric renal disease, none from this cohort with this specific CLDN19 variant has evidence for renal disease to date.

Conclusions: CLDN19-related maculopathy can resemble and be mistaken as prior ocular toxoplasmosis infection. Unlike other CLDN19 mutations, the homozygous variant in this cohort has not been associated with renal disease to date. Genetic maculopathy should be considered in children with macular scars presumed to be related to prior ocular toxoplasmosis infection, particularly when the scarring is bilateral or familial.