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Kidney Week

Abstract: SA-PO575

Dent Disease Presenting as Night Blindness

Session Information

  • Genetic Diseases: Diagnosis
    November 05, 2022 | Location: Exhibit Hall, Orange County Convention Center‚ West Building
    Abstract Time: 10:00 AM - 12:00 PM

Category: Genetic Diseases of the Kidneys

  • 1102 Genetic Diseases of the Kidneys: Non-Cystic

Authors

  • Miller, Robin, Rady Children's Hospital San Diego, San Diego, California, United States
  • Arnett, Justin J., University of California at San Diego Department of Ophthalmology at the Shiley Eye Institute, La Jolla, California, United States
  • Shayan, Katayoon, Rady Children's Hospital San Diego, San Diego, California, United States
  • Borooah, Shyamanga R., University of California at San Diego Department of Ophthalmology at the Shiley Eye Institute, La Jolla, California, United States
  • Carter, Caitlin E., Rady Children's Hospital San Diego, San Diego, California, United States
Introduction

Dent Disease is an X-linked inherited tubulopathy that results in low molecular weight proteinuria, hypercalciuria, nephrocalcinosis, and progressive kidney dysfunction. Typical clinical manifestations in children include rickets, polyuria, and nephrolithiasis. We report a case of night blindness as the initial presentation of Dent Disease.

Case Description

A 16 yo healthy male with no family history of kidney disease presented with progressive night blindness and peripheral vision loss. He was found to have vitamin A deficiency and visual symptoms improved with vitamin A supplementation. Evaluation for underlying causes of vitamin A deficiency revealed renal dysfunction (serum creatinine 1.2 mg/dL, eGFR 65 ml/min by Schwartz 2) and nephrotic range proteinuria (3.5 gm/day). Urinary retinol binding protein to creatinine ratio was markedly elevated at >6667mcg/g (normal <190 mcg/g), suggestive of loss of retinol binding protein as the etiology of his vitamin A deficiency. Kidney biopsy demonstrated fibrous glomerular crescents, glomerulosclerosis, and tubular atrophy with moderate interstitial fibrosis. Evaluation for immunologic and genetic causes of glomerular disease was unrevealing. Genetic testing confirmed a pathogenic mutation in CLCN5, one of the two genes known to cause Dent Disease. The patient was subsequently found to have low bone mineral density by DEXA and hypercalciuria.

Discussion

Dent Disease due to CLCN5 mutation results in the inability of the proximal tubule to reabsorb low molecular weight proteins from the glomerular filtrate. This includes retinol binding protein, and vitamin A deficiency is a known sequelae of Dent Disease, however resultant vision loss has not previously been reported as the presenting finding in Dent Disease. In addition, while Dent Disease is typically considered a primarily tubular disorder, our patient had significant glomerular pathology including fibrous and fibrocellular crescents, which are rarely reported manifestations of Dent Disease but may play a role in its progression. Identifying early symptoms of Dent Disease allows for prompt treatment which could limit morbidity and mortality.