Fanconi Syndrome
In dogs and cats, Fanconi syndrome can be inherited (with no known cause) or acquired (caused by heavy metal poisoning, drugs, chemicals, hypoparathyroidism, or kidney disease. In most of the forms, a toxin builds up in the renal tubular cells. In the idiopathic forms, the presumed toxin is unknown. The disease is characterized by increased urinary excretion of sodium, potassium, calcium, phosphorus, and magnesium, uric acid and other organic acids. Because of the number of different transport mechanisms involved in Fanconi syndrome, it is likely that individual transporters themselves are affected.
Signs of Fanconi Syndrome
Clinical signs of Fanconi syndrome include increased urination; in young animals, growth retardation and rickets may develop. Idiopathic Fanconi syndrome often progresses to chronic kidney failure.
In case of hypoparathyroidism, affected animals may have muscle twitching, increased urination, intense thirst, loss of appetite, and loss of hair around the eyes.
Breeds Affected by Fanconi Syndrome
In Basenjis, Fanconi syndrome is an autosomal recessive disease and the genetic defect 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 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. But if you give insulin to affected dog, it can harm, or even kill him
Treatment of Fanconi Syndrome
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. The sign of the disease may vary from one dog to another.
Glucose (sugar) is one of the first nutrients that can be detected in the urine of the affected dog. There is a simple test that you can do at home to be alerted to this early sign. If sugar is present, this is not a diagnosis of Fanconi syndrome. sugar can be present for other reasons (females in estrus, for example, may show sugar in their urine).
If glucose is present in the urine, have your veterinarian run a blood test for glucose to rule out diabetes. If there is not an abnormal amount of blood glucose, Fanconi syndrome is suspect and further testing needs to be done.
References:
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.
3. Basenjis. Mary Lou Kenworthy
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