ABCA4-associated maculopathy suspected to be ocular toxoplasmosis

Summary

This case report, published in the BMC Ophthalmology, describes a young adult with long-standing central vision loss and macular lesions that looked like coloboma and were suspected to be ocular toxoplasmosis. After eye imaging, testing and 20 years of follow-up, the authors found that the real cause was ABCA4-associated retinopathy, with two pathogenic ABCA4 variants.

The report says this broadens the known range of ABCA4 disease to include coloboma-like macular lesions. It also shows that more than one retinal problem can be present at the same time, so genetic testing can still be useful even when the eye signs do not point clearly to an inherited disorder.

Keywords: ABCA4-associated retinopathy, inherited retinal disease, macular coloboma, macular dystrophy, ocular toxoplasmosis, central vision loss, genetic testing.

Abstract

Background
Macular coloboma is a rare congenital anomaly that may mimic other retinal pathologies, including infectious disease and inherited retinal dystrophies. We report a young adult male with longstanding central vision loss and bilateral macular atrophic lesions resembling coloboma, ultimately found to harbour bi-allelic pathogenic variants in ABCA4.

Case presentation
The patient underwent comprehensive ophthalmologic evaluation, including fundus imaging, optical coherence tomography (OCT), fundus autofluorescence (FAF), molecular genetic analysis, and segregation analysis. Macular dystrophy gene panel sequencing was performed. The patient was followed up for 20 years. OCT confirmed neurosensory retinal and choroidal loss at the fovea. Electro-diagnostics showed cone system dysfunction with preserved rod function. Genetic testing identified compound heterozygosity for two pathogenic ABCA4 variants (c.2160+1G>C and p.Thr1526Met), confirming ABCA4-associated retinopathy

Conclusion
This case expands the phenotypic spectrum of ABCA4-related disease to include macular coloboma-like lesions. It also raises the possibility of coexisting retinal pathologies. Genetic testing should be considered in young patients with progressive visual loss and coloboma-like macular lesions, even in the absence of family history or evidence of intraocular inflammation.