Didanosine-Associated Retinal Toxicity in a Patient With a Mutation in the CRB1 Gene

Purpose: This article describes a case of didanosine (DDI)-associated retinal toxicity in a patient with a heterozygous pathogenic variant in the CRB1 gene. Methods: Case report. Results: A middle-aged patient with HIV controlled on HAART therapy, and a remote 10-year year history of treatment with DDI and tenofivir, presented with external ophthalmoplegia and well-circumscribed, midperipheral patterns of bilateral pigmentary retinopathy and chorioretinal atrophy in both eyes. Genetic testing revealed a heterozygous pathogenic variant in the CRB1 gene that encodes a protein (Crumbs homolog 1) involved in regulation of cell polarity and junctions and is localized adjacent to mitochondria in the ellipsoid and myoid area. Conclusions: This case highlights a potential role for genetic susceptibility to retinal toxicity in DDI-associated retinal toxicity. Large, prospective pharmacogenomics studies may be informative to further elucidate the role of genetic risk factors in drug-induced retinal toxicity.

MAXILLARY MUCOCOELE A RARE ENTITY

Mucoceles are accumulations of trapped mucus, forming cystic expansile lesions. Maxillary sinus mucoceles are rare amongst paranasal sinus mucoceles, usually being a late sequel of Caldwell-Luc surgery. We present a case of a maxillary sinus mucocele due to a molar root canal treatment in a middle aged patient, reported to highlight its unusual etiology. Keywords Mucocele