Dent disease presenting with nyctalopia and electroretinographic correlates of vitamin A deficiency

PURPOSE: To report a unique case of Dent Disease presenting with nyctalopia associated with vitamin A deficiency and abnormal electroretinogram findings without prior systemic symptomatology. OBSERVATIONS: A 16-year-old male presented with a several month history of nyctalopia and peripheral vision deficits. Central visual acuity, anterior and posterior segment examinations, and macular optical coherence tomography were unremarkable. Electroretinogram (ERG) testing revealed a rod-cone dystrophic pattern, with further workup demonstrating serum vitamin A deficiency (VAD). Laboratory evaluation revealed renal dysfunction and proteinuria with a significantly elevated urinary retinol-binding protein (RBP). Kidney biopsy showed glomerular and tubular disease. Genetic screening for inherited renal disease was performed identifying a hemizygous pathogenic variant c.2152C>T (p.Arg718*) in the Chloride Voltage-Gated Channel 5 (CLCN5) gene, confirming the diagnosis of X-linked Dent Disease. Following vitamin A supplementation, our patient reported resolution of nyctalopia and reversal of abnormal ERG findings were demonstrated. CONCLUSIONS AND IMPORTANCE: To our knowledge, this is the first case in the literature describing Dent disease solely presenting with ophthalmic symptoms of nyctalopia and abnormal electroretinogram findings that later reversed with vitamin A repletion. This case stresses the importance for clinicians to consider renal tubular disorders in the differential for VAD.