Acquired Fanconi syndrome is the generalized dysfunction of the proximal tubule of the kidney caused by toxic exposure to certain drugs and heavy metals as well as monoclonal gammopathy. This disorder can occur in children and adults and is dependent on toxin exposure history. Common drugs that cause acquired Fanconi syndrome include aminoglycoside antibiotics, tetracycline antibiotics, chemotherapy agents (cisplatin, ifosfamide, carboplatin), antiviral drugs (tenofovir, adefovir), and anticonvulsant agents (valproic acid). Heavy metals such as cadmium, lead, mercury, platinum, and uranium are also implicated in acquired Fanconi syndrome. Monoclonal gammopathy due to multiple myeloma or monoclonal gammopathy of undetermined significance (MGUS) tends to occur in the adult population only.

Clinical manifestations include normoglycemic glycosuria, aminoaciduria, hypophosphatemia, hypokalemia, hypouricemia, and proximal renal tubular acidosis (type 2 renal tubular acidosis). Growth failure is a common presentation in children due to electrolyte deficiencies. Complications such as rickets, osteomalacia, muscle weakness, and confusion / lethargy can occur. Diagnosis is made with laboratory and urine testing. Treatment includes withdrawal of the offending agent, reversal of acidosis, and replacement of fluids and electrolytes.