Common Symptoms
Renal cystadenocarcinoma and nodular dermatofibrosis is an inherited genetic predisposition to kidney, dermal and uterine cancer in dogs. This condition manifests as a combination of abnormal masses in the kidneys and the skin of both male and female dogs and also the uterus in female dogs. Affected dogs usually present around 6.5 years of age with small, firm bumps under the surface of the skin, more commonly located on the limbs and head. The kidney tumors often form nodular masses and cysts that can cause the kidneys to become enlarged, abnormally shaped and scarred. Affected dogs often show signs of chronic kidney disease which may include frequent urination, blood in the urine, frequent drinking, depression, inappetence and weight loss. The disease typically presents over the age of 5, and tumors may not develop until dogs are 9 to 11 years of age. The average age of death for affected dogs is 9.3 years due to renal failure or metastatic disease. Puppies that inherit two copies of the FLCN gene Mutation most likely die very early in gestation; therefore, breeding two dogs with renal cystadenocarcinoma and nodular dermatofibrosis may result in reduced litter size.
Testing Tips
Genetic testing of the FLCN gene will reliably determine whether a dog is a genetic Carrier of renal cystadenocarcinoma and nodular dermatofibrosis. Renal cystadenocarcinoma and nodular dermatofibrosis is inherited in an Autosomal Dominant manner in dogs meaning that dogs only need to inherit one copy of the mutated gene to be at-risk for the disease. Puppies that inherit two copies of the genetic Mutation most likely die In Utero. Each pup that is born to a parent carrying one copy of the mutation has a 50% chance of inheriting one copy of the FLCN gene mutation and being at-risk for the disease. Because symptoms do not appear until adulthood, genetic testing should be performed before breeding. Reliable genetic testing is important for determining breeding practices. In order to eliminate this mutation from breeding lines and to avoid the potential of producing affected pups, breeding of known carriers is not recommended. Dogs that are not carriers of the mutation have no increased risk of having affected pups due to this mutation.
There may be other causes of this condition in dogs and a normal result does not exclude a different mutation in this gene or any other gene that may result in a similar genetic disease or trait.
References
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Jónasdóttir TJ, Mellersh CS, Moe L, Heggebø R, Gamlem H, Ostrander EA, Lingaas F. Genetic mapping of a naturally occurring hereditary renal cancer syndrome in dogs. Proc Natl Acad Sci U S A. 2000 Apr 11; 97(8):4132-7.
[PubMed: 10759551]
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Lingaas F, Comstock KE, Kirkness EF, Sørensen A, Aarskaug T, Hitte C, Nickerson ML, Moe L, Schmidt LS, Thomas R, Breen M, Galibert F, Zbar B, Ostrander EA. A mutation in the canine BHD gene is associated with hereditary multifocal renal cystadenocarcinoma and nodular dermatofibrosis in the German Shepherd dog. Hum Mol Genet. 2003 Dec 1; 12(23):3043-53.
[PubMed: 14532326]
