Fanconi syndrome is an absorption problem in the tubules that make up the kidney. In a normally functioning kidney the small tubules reabsorb minerals, blood sugar, amino acids, and water to keep the body in a metabolic balance that leads to normal functioning of all body systems. In dogs that have the hereditary Fanconi syndrome the tubules do not correctly reabsorb these essential compounds which are simply removed from the body in the urine, resulting in metabolic imbalances that will eventually lead to death. As with most syndromes the condition cannot be eliminated but it can be managed and kidney function supported through several different treatment options. The earlier diagnosis is made then the better the outlook for managing the condition.
There are several breeds that are at greater risk to have Fanconi syndrome with the Basenji being the breed most prone to the condition with about 10% of all purebreds diagnosed. In other breeds such as the Shetland Sheepdog, Norwegian Elkhound, and the Schnauzer the rate is much lower although still noticeably higher than other breeds. The condition is not usually seen in puppies but will start to cause some behavioral and health conditions when the puppy reaches maturity at about a year old. Dogs can develop the condition at any time during their adult or senior years but the most common age for the diagnosis is three to seven years. Fanconi syndrome cannot be caused by any other disease or trauma to the kidney, it can only occur through genetics.
Typically the first signs of the condition are very similar to diabetes mellitus and can be easily misdiagnosed if the vet does not complete blood tests. Excessive urination and drinking are typically the first signs, with owners often coming to the vet because the dog is urinating in the house even after being housetrained. If not treated the dog will start to lose weight and become very lethargic as the metabolic needs of the cells are not being met due to the depletion of the amino acids, sugars, and electrolytes in the blood. This weight loss can be very gradual over time or can appear quite suddenly depending on the functioning or loss of function of the kidneys. Often the later the onset of the condition the more rapid the development of the symptoms will occur.
During this time the dog will become gradually weaker, may start to vomit, show signs of anemia, and even refuse to eat or to exercise. Some dogs may also show high incidents of urinary tract infections, especially when the condition is slow in progressing.
Although there is no cure for Fanconi syndrome, once diagnosed through blood and urine tests the vet will prescribe various types of treatments to minimize the progression of the condition. Generally antibiotics will be provided to treat any urinary infections that may exist. Feeding high quality but low protein diets to reduce the stress on the kidney as well as using specific types of supplements to increase the intake of nutrients, vitamins, and minerals to the dog's diet is also usually a part of treatment plans.