Dent disease is a rare X-linked proximal tubulopathy characterised by low-molecular-weight proteinuria, frequently associated with hypercalciuria, nephrocalcinosis, and progressive renal failure. We report the case of a previously healthy 15-year-old boy in whom isolated proteinuria was detected during a screening examination. Subsequent hospitalisations confirmed the presence of tubular proteinuria and hypercalciuria. Genetic testing identified a pathogenic mutation in the CLCN5 gene, establishing the diagnosis of Dent disease. This case underscores the importance of urinary protein profiling and highlights the value of genetic testing in the diagnostic evaluation of proteinuria. Early diagnosis enables timely initiation of measures to reduce hypercalciuria, introduce renoprotective treatment, and avoid ineffective and potentially harmful immunosuppressive therapy.

gene mutation, Dent disease, low molecular weight proteinuria, renal tubule disorders, hypercalciuria