Fanconi Syndrome

Clinical signs typically include polyuria and polydipsia (increased amount and frequency of urination and drinking), muscle wasting, weight loss, metabolic acidosis, and poor coat quality. In dogs with Fanconi syndrome, urinalysis findings frequently identify the presence of glucose despite normal serum glucose levels. The onset of clinical signs typically varies between 4 and 7 years of age. The disease is caused by the impaired reabsorption capacity of the proximal renal tubules leading to urinary leakage of essential metabolites such as glucose, electrolytes, amino acids, and proteins. It has been speculated that low-level amounts of heavy metals could speed up kidney damage in affected dogs. This would explain the varying age of onset. Among Basenjis, the prevalence of the disease has been estimated to be about 10%.

Treatment is aimed at slowing the progression of the kidney disease and preserving quality of life through nutritional and medical supportive care. With appropriate treatment, affected dogs typically live about 5 years after the development of clinical signs. If left untreated, the disease leads to death secondary to renal failure.

There are many responsibilities to consider when breeding dogs. Regardless of test results it is important that your dog is in good general health and that you are in a position to care for the puppies if new responsible owners are not found. For first time or novice breeders, advice can be found at most kennel club websites.

This disease is autosomal recessive meaning that two copies of the mutation are needed for disease signs to occur. A carrier dog with one copy of the Fanconi Syndrome mutation can be safely bred with a clear dog with no copies of the Fanconi Syndrome mutation. About half of the puppies will have one copy (carriers) and half will have no copies of the Fanconi Syndrome mutation. A dog with two copies of the Fanconi Syndrome mutation can be safely bred with a clear dog. The resulting puppies will all be carriers. Puppies in a litter which is expected to contain carriers should be tested prior to breeding. Carrier to carrier matings are not advised as the resulting litter may contain affected puppies. Please note: It is possible that disease signs similar to the ones caused by the Fanconi Syndrome mutation could develop due to a different genetic or clinical cause.