Fanconi Syndrome
Fanconi Syndrome affects the proximal convoluted tubules (PCTs) of the nephron, the functional unit of the kidney. This hampers the adequate reabsorption of glucose, amino acids, bicarbonate, sodium, potassium, calcium, phosphate, lactate, ketones, and carnitine to the blood, causing them to be lost in the urine. The resultant solute diuresis (osmosis) can cause dehydration, electrolyte imbalances, vitamin and mineral deficiencies, and metabolic acidosis leading to progressive renal failure if left untreated.
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Signs and symptoms
Symptoms of abnormal kidney function in affected dogs most commonly include increased urination (polyuria) and excessive drinking (polydipsia) in an attempt to replenish their water stores. Less often, dogs may have weight loss (despite a normal appetite), vomiting, and weakness.
Affected dogs typically present with clinical signs of abnormal kidney function at middle-age with an average onset age between four to seven years of age. Glucose in the urine (glucosuria) without increased glucose in the blood (hyperglycemia) may be noted on laboratory testing before clinical symptoms develop. -
Diagnosis
Diagnosis is made based on clinical history, physical examination, genetic testing, and ruling out other causes of similar symptoms. Serum chemistry and urinalysis as well as venous blood gas analyses are indicated to define the extent of the tubular defect and acidosis. Urinalysis typically reveals glycosuria without hyperglycemia and ketonuria. Additional urine metabolic screening from dogs with Fanconi Syndrome often shows a generalized aminoaciduria and lactic aciduria. While there is severe aminoaciduria, there is either no or only mild proteinuria.
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Treatment
While Fanconi Syndrome is not curable, it is treatable. If an affected dog is not treated, the disease can progress to chronic kidney failure. A highly effective therapeutic protocol developed and modified over the years focuses on correction of the various losses with particular attention to bicarbonate, normalizing electrolytes and minerals, and providing a high quality diet. Dogs with Fanconi Syndrome diagnosed and treated early will usually have normal BUN (blood urea nitrogen) and creatinine values. Those diagnosed later in their disease will show some azotemia (elevated BUN and/or creatinine), which may require modification of the protocol to address both the Fanconi (failure to reabsorb solutes from the urine) and renal insufficiency (failure to lose toxic solutes in the urine).
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What to do if your dog is at risk
Actions
- Closely monitor your dog for changes in their drinking and urination patterns.
- Regular veterinary visits and laboratory testing will be vital to catching this disease at an early stage where it can be more easily managed.
- Dietary and medication recommendations are based on how clinically advanced the Fanconi Syndrome is. Follow your veterinarian’s recommendations.
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Genetic Information
It is important to note that Fanconi Syndrome has been suspected to occur secondary to consumption of certain jerky treats. Fanconi Syndrome can also be acquired secondary to infections, chemical additives, and certain medications. Even dogs without risk from this variant can develop Fanconi Syndrome: regular veterinary check ups and monitoring of a dog's health is key to catching and treating the first signs of Fanconi Syndrome.
Fanconi Syndrome is recessive, that is, a dog requires two copies of the variant to show signs of the disease from the variant. This variant was first described in Basenji.
Gene names:
FAN1 ‐ chr
Inheritance type:
recessive
Citations:
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Breeds affected
This health condition affects the following breeds
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