Common Symptoms
Cleft palate and syndactyly is an inherited developmental disease affecting the Nova Scotia duck tolling retriever. Affected dogs present at birth with facial deformities of variable severity which include incomplete fusion of the upper lip (clefts) under one or both nostrils which often extends to involve incomplete fusion of the palate and an open connection between the nasal cavity and mouth. In addition to malformation of the face and mouth, most affected dogs also display partial or complete fusion of the third and fourth toes (syndactyly) on any or all of their feet.
At least one other genetic Mutation (in the canine DLX6 gene) has also been associated with cleft palate in the Nova Scotia duck tolling retriever. Therefore, obtaining normal results on this ADAMTS20 gene test does not completely exclude cleft palate in a pedigree.
Breed-Specific Information for the Nova Scotia Duck Tolling Retriever
The Mutation of the ADAMTS20 gene associated with cleft palate and syndactyly has been identified in Nova Scotia duck tolling retrievers. Though the exact frequency in the overall Nova Scotia duck tolling retriever population is unknown, approximately 3.1% out of 97 Nova Scotia duck tolling retrievers tested were carriers of the mutation.
Testing Tips
Genetic testing of the ADAMTS20 gene in the Nova Scotia duck tolling retriever will reliably determine whether a dog is a genetic Carrier of cleft palate and syndactyly. Cleft palate and syndactyly (Nova Scotia duck tolling retriever type) is inherited in an Autosomal Recessive manner in dogs meaning that they must receive two copies of the mutated gene (one from each parent) to develop the disease. In general, carrier dogs do not have features of the disease but when bred with another carrier of the same Mutation, there is a risk of having affected pups. Each pup that is born to this pairing has a 25% chance of inheriting the disease and a 50% chance of inheriting one copy and being a carrier of the ADAMTS20 gene mutation. 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 to each other is not recommended. Nova Scotia duck tolling retrievers that are not carriers of the mutation have no increased risk of having affected pups.
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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Wolf ZT, Brand HA, Shaffer JR, Leslie EJ, Boaz A, Willet CE, Cox TC, McHenry T, Narayan N, Feingold E, Wang X, Sliskovic S, Karmi N, Safra N, Sanchez C, Deleyiannis FWB, Murray JC, Wade CM, Marazita ML, Bannasch DL. Genome-Wide Association Studies in Dogs and Humans Identify ADAMTS20 as a Risk Variant for Cleft Lip and Palate. PLoS Genet. 2015 Mar 23;11(3):e1005059. doi: 10.1371/journal.pgen.1005059.
[PubMed: 25798845]
