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Abstract:
Background:Dent disease is an X-linked renal proximal tubular disorder characterized by low-molecular-weight (LMW) proteinuria, hypercalciuria and nephrocalcinosis/nephrolithiasis that frequently develops chronic kidney disease (CKD) over time. The aim of this study is to describe the long term outcome of patients with Dent disease.
Methods:this is a retrospective, observational study including affected male patients who were diagnosed during childhood. We measured urine and blood parameters related to the expected evolution of the disease and registered radiological findings, estimated glomerular filtration rate (GFR) and the treatment they received.
Results:Seven male patients were included, all of them carrying CLCN5 gene pathogenic variants. They were referred to the Pediatric Nephrology Service at the median age of 3 years (range 11months-13years) due to proteinuria (3patients), proteinuria and hypercalciuria (1), kidney failure (1) and familial study (2). The median rate follow-up time was 9 years (range 2-20.5 years). All of the patients have, at last follow-up, LMW proteinuria and 5 patients have hypercalcemia and nephrocalcinosis. None of them have nephrolithiasis or hematuria. Additional manifestations of proximal tubular dysfunction are also present with variable frequencies, such as hypokalemia (3patients) or glycosuria (1). Three patients have hypophosphatemia, low bone mineral density and take phosphate supplements from the adolescence. One patient showed growth failure and received Growth Hormone Therapy. At diagnosis, the median estimated GFR was 96ml/min/1.73m2 (range 13-235) and one patient had CKD. During follow-up period, 4 patients developed CKD (II-III), median GFR 82ml/min/1.73m2 (range 51-157) with the median age of 18years (range 13-18).
Four patients need thiazide and amiloride combination drugs, 5 receive potassium or phosphate supplements and 3 vitamin D supplements.
Conclusion:Dent disease is a rare condition with poor long-term prognosis that progress to CKD at early adulthood and may develop hypophosphatemia with risk of osteomalacia. Genetic diagnosis is essential for the study of relatives.
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