Severe Fanconi Syndrome with Fracturing Osteopathy in a Young Adult: Late Revelation of Dent Disease at Age 37

A 37-year-old man from a consanguineous family presented with diffuse bone pain, recurrent fractures, and a waddling gait. Laboratory workup revealed severe hypophosphatemia (17 mg/L), markedly elevated alkaline phosphatase, hypercalciuria three times above normal, glycosuria, tubular proteinuria (450 mg/24h), nephrocalcinosis, and hyperchloremic metabolic acidosis. Bone imaging revealed diffuse demineralization, vertebral compression fractures, and a honeycomb appearance of the vertebrae ("beehive" aspect). The association of chronic hypophosphatemia, hypercalciuria, nephrocalcinosis, and tubular proteinuria pointed toward a clinical diagnosis of Dent disease. Genetic analysis was not feasible locally, as no genetic testing for hereditary nephropathies is currently available in Algeria and export of blood samples is restricted; a private send-out to CERBA (France) was cost-prohibitive for the patient. The diagnosis therefore remains purely clinical. This X-linked disorder (mutations in CLCN5 or OCRL) combines hypercalciuria, nephrocalcinosis, low-molecular-weight proteinuria, and incomplete Fanconi syndrome. Chronic hypophosphatemia is responsible for severe osteomalacia. Management relies on oral phosphate supplementation, acidosis correction, and treatment of hypercalciuria (low-salt diet, thiazide diuretics).