Fanconi syndrome is a disorder in which the proximal tubular function of the kidney is impaired, resulting in decreased reabsorption of electrolytes and nutrients back into the bloodstream. Compounds involved include glucose, amino acids, uric acid, phosphate, and bicarbonate.

The reduced reabsorption of bicarbonate results in type 2 or proximal renal tubular acidosis, which may in some cases exist on its own, or more usually in combination with the Fanconi syndrome.

In many cases, the disease is developed in the context of multi-system genetic diseases(e.g Cystinosis, Galactosemia). And in many others, high exposure to toxic substances(e.g heavy metals, drugs) is discovered as the main risk factor. The disease can also develop as a consequence of other acquired diseases(e.g multiple myeloma, PNH)^[1].

Patients mainly present with dehydration, growth failure, rickets(children) and osteomalacia(adults)^[2][3].

It is named after Guido Fanconi, a Swiss pediatrician; this may be a misnomer since Fanconi himself never identified it as a syndrome^[2].

It should not be confused with Fanconi anemia, a separate disease^[4].