Renal Fanconi syndrome: Failure of the tubules in the kidney to reabsorb small molecules, causing increased urinary loss of electrolytes (sodium, potassium, bicarbonate), minerals, glucose, amino acids, and water. These losses results in polyuria (excessive urination), polydipsia (excessive intake of fluid), dehydration (from the excess urination) hypophosphatemic rickets (due to loss of phosphate in the urine), and growth retardation (due to the renal disease). Treatment is by replacing the renal losses and supplementing with citrate to alkalinize the blood. Phosphate replacement prevents and heals the rickets. Vitamin D helps the intestinal absorption of phosphate.
The syndrome is named for the Swiss pediatrician, Guido Fanconi, who also first reported Fanconi anemia.