Fanconi Syndrome

Fanconi Syndrome is a hereditary or acquired form of generalized kidney disorder. It is usually characterized by the wasting of nutrients and salts, such as glucose, amino acids, phosphates,and bicarbonates resulting in increased urinary excretion of sodium, potassium, calcium, phosphorus, magnesium, uric and other organic acids. In dogs and cats, Fanconi syndrome can be inherited or acquired. The acquired form is caused by heavy metal poisoning, drugs, chemicals, hypoparathyroidism, or kidney disease resulting in accumulation of toxins in the renal tubular cells. The causes of idiopathic Fanconi syndrome have not been determined and the disease often progresses to chronic kidney failure.

The most common sign is increased urination. In case of hypoparathyroidism, muscle twitching, increased urination, intense thirst, loss of appetite, and loss of hair around the eyes are commonly seen. Fanconi Syndrome affects several breeds. In Basenjis, the genetic defect is inherited and is considered to be of the late-acting, lethal type because of the progression to chronic renal failure. Other breeds affected by idiopathic Fanconi syndrome include the Yorkshire Terrier, Shetland Sheepdog, Whippet, Border Terrier, and Norwegian Elkhound. If lost nutrients are not replaced, it can lead eventually to death. Since dogs with Fanconi syndrome often have elevated levels of blood sugar, it is sometimes misdiagnosed as diabetes. There is a treatment protocol which, when followed accurately, can add years to the affected dog's life. It consists of treating the signs and replacing the lost nutrients. You must work closely with your veterinarian and do continual testing to determine which nutrients must be replaced and in which amounts.


  1. Renal Tubular Disorders. K.M. James
  2. Fanconi's syndrome in a dog with primary hypoparathyroidism. Freeman LM, Breitschwerdt EB, Keene BW, Hansen B. In: J Vet Intern Med. 1994 Sep-Oct;8(5):349-54

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