The kidneys are essential in the urinary system and also serve homeostatic functions such as the regulation of electrolytes, maintenance of acid–base balance, and regulation of blood pressure (via maintaining salt and water balance). Besides serving as natural filter of the blood, the kidneys are also responsible for the reabsorption of water, glucose, amino acids and other vital nutrients back into the body.
Fanconi syndrome is a disorder in which kidneys are no longer able to reabsorb vital nutrients back into the body. In this condition, there is a defect in the proximal renal tubules (first part of the tubule to process fluid after it is filtered through the glomerulus) in the kidneys where the reabsorption of vital nutrients takes place. These essential nutrients are excessively excreted into the urine. This leads to loss of sodium, potassium, glucose, phosphate, bicarbonate, and amino acids from the body, resulting in different complications such as dehydration, electrolyte imbalance, poor growth etc.
This condition can occur in any dog but basenji is the most affected breed. It is presumed to be an inherited trait in this breed, but the mode of inheritance is unknown. Besides basenjis, this condition is sporadically seen in other breeds such as border terriers, Norwegian elkhounds, whippets, Yorkshire terriers, Labrador retrievers, Shetland sheepdogs, and mixed-breed dogs, but the cause remains idiopathic (unknown).
Dogs that are affected with this disorder usually show signs anywhere from 1 to 7 years of age. The earliest signs are excessive drinking and urination, because the kidneys are unable to conserve water. Because of the loss of nutrients and electrolytes in the urine, the dog may experience weight loss and muscle weakness. The condition may worsen slowly over several years, or may progress rapidly to kidney failure with signs such as poor appetite, extreme loss of weight, lethargy, vomiting, and pale gums due to anemia. Dogs with Fanconi syndrome are prone to urinary tract infections due to the sugar in the urine.
