Fanconi Syndrome in Basenji Dogs

Renal Tubular Dysfunction

History

  • Renal Tubular Dysfunction
  • Commonly known as Fanconi Syndrome
  • First discovered in 1976 by Easley and Breitschwerdt
  • There are acquired and inherited forms of Fanconi Syndrome
  • Is chronic and persistent in most cases
  • May be transient in dogs with Fanconi syndrome secondary to a resolvable initiating cause.
  • Long term prognosis varies with many dog owners choosing to euthanize and others finding a way for their dogs to continue living a full life on various supplement regiments.
  • Prevalence of Fanconi Syndrome in Basenjis is estimated to be around 10% of the population.

What is Fanconi Syndrome in Basenjis?

  • Fanconi Syndrome is disease in which there is a noticeable impairment of the proximal portion of the renal tube, resulting in excessive urinary losses of water, glucose, phosphate, sodium, potassium, bicarbonate, uric acid, amino acids, and protein.
  • Common clinical signs include polyuria and polydipsia.
  • Other clinical signs include weight loss despite normal appetite, weakness, urinary incontinence, and a poor hair coat.
  • Age at time of diagnosis varies but tends to be around 4-6 years of age, with the majority of tested Basenji's aging around 5 years of age.
  • If not caught early enough, Fanconi Syndrome can lead to renal failure and eventually death.
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Diagnosis

  • Absolute diagnosis is determined with a venous blood gas test.
  • Diagnosis can also be found through a blood chemistry tests that looks specifically at calcium, potassium, phosphorus, BUN, and creatinine, which would all be low if the dog truly had fanconi syndrome.
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Diagnosis Problems

  • There have been substantial variations in the type and severity of nutrient absorption defects, which can make it difficult to pinpoint the exact cause of symptoms presented.
  • Many times, investigations regarding the origin of Fanconi Syndrome are made extremely difficult, if not impossible, by the lack of family history due to adoptions and dogs that have been re-homed without proper background paperwork.
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Genetic Transmission

  • Genetic testing of the FAN1 gene can determine whether the dog is a genetic carrier of Fanconi syndrome.
  • Researchers were able to identify a deletion in the last exon of the FAN1 for which homozygosity for the deletion allele is believed to be strongly associated with the Fanconi syndrome phenotype.
  • It is an Autosomal Recessive gene, which means they must inherit two copies of the mutated gene (one from each parent) in order to develop the disease.
  • Researchers have found a linkage between markers from CFA3 and the disease phenotype.
  • I was unable to find any documented canine specific phenotype or genotype visuals, but if you search for human-Fanconi syndrome, they will be very similar.

Production

  • Many breeders find it difficult to sell their breeding stock if they are aware of the Fanconi syndrome as customers know that it can be transmitted genetically and onset can be anywhere from birth to 5+ years of age.
  • The lifespan of affected dogs can be anywhere between a couple months or several years depending on age at diagnosis and whether or not dietary needs were managed well enough.

Eradication Methods and Barriers

  • As of now, treatment is centered on the use of supplements to minimize the long term effects of loss of nutrients due to Fanconi Syndrome.
  • Treatments are focused on the control of chronic acidosis and electrolyte imbalances.
  • Barriers include cost of medical care, cost of supplements, and overall stress on the animal.

References

Gonto, Steve, M.M.Sc., Ph.D. Fanconi Renal Disease Management Protocol for Veterinarians. Management Protocol for Veterinarians. N.p.: n.p., February 29, 2016. Print.

Mainka, Susan A. "Fanconi Syndrome in a Basenji." Can Vet Journal 26 (1985): 303-05. Print.

Medow, M. S., R. Reynolds, K. C. Bovee, and S. Segal. "Proline and Glucose Transport by Renal Membranes from Dogs with Spontaneous Idiopathic Fanconi Syndrome." Proceedings of the National Academy of Sciences 78.12 (1981): 7769-772. Web. 29 Apr. 2016.

Yearley,, Jennifer H., DVM, MA, Dale D. Hancock, DVM,PhD, and Katrina L. Mealey, DVM, PhD, DACVIM, DACVCP. "Result Filters." National Center for Biotechnology Information. U.S. National Library of Medicine, 1 Aug. 2004. Web. 29 Apr. 2016. <http://www.ncbi.nlm.nih.gov/pubmed/15328712>.

My Question to You

So what do you think could be done to further the research into treatment plans for Basinjis with Fanconi Syndrome?

If you were in charge of prescribing certain supplements to help lessen the burden that Fanconi Syndrome causes, what would you choose?