Cleft Lip/Palate and Syndactyly (CLPS) in Nova Scotia Duck Tolling Retrievers
The CLPS genetic variant causes development of cleft palate and/or cleft lip, sometimes also accompanied by syndactly (fused toes), in Nova Scotia Duck Tolling Retriever puppies.
Phenotype: The phenotype of affected puppies can vary from only a cleft palate (hole in the roof of the mouth) to cleft palate and cleft lip (split in the lip that can occur on one or both sides of the mouth). In both cases puppies may also have syndactyly (fusion of the middle two digits of the feet).
Mode of Inheritance: Autosomal recessive
Alleles: N = Normal, A = Cleft lip/palate and syndactyly (CLPS)
Breeds appropriate for testing: Nova Scotia Duck Tolling Retriever
Explanation of Results:
Dogs with N/N genotype will not have this form of cleft lip/palate and syndactyly and cannot transmit this CLPS variant to their offspring.
Dogs with N/A genotype will not have this form of cleft lip/palate and syndactyly, but are carriers. They will transmit this CLPS variant to 50% of their offspring. Matings between two carriers are predicted to produce 25% CLPS-affected puppies.
Dogs with A/A genotype will be affected to varying degrees by cleft lip/palate and syndactyly. They will transmit this CLPS variant to all of their offspring.
Cleft palate is a hole (cleft) in the roof of the mouth (palate) that occurs during development of the puppy. Puppies are then born with a cleft palate. Cleft lip is a split in the lip that can occur on one or both sides of the mouth. Syndactyly is the fusion of the middle two digits of the feet.
In the Nova Scotia Duck Tolling Retriever, or Toller, breed, multiple genetic causes of cleft palate have been identified. A test is already available for a variant known as CP1 in Tollers, which causes cleft palate. A different variant that causes a second form of cleft lip and cleft palate called CLPS has been identified by scientists from the Bannasch Laboratory at the University of California, Davis and the Wade Laboratory from the University of Sydney.
CLPS is inherited as an autosomal recessive disease. Affected puppies inherit two mutant copies of this defective gene, one from each parent. The phenotype of puppies with two copies of CLPS can vary from cleft palate only to cleft lip and cleft palate, and in both cases puppies may also have syndactyly. Dogs that have 1 copy of the CLPS mutation (carriers) are completely normal and can be safely bred to N/N dogs in order to maintain diversity within the breed and select for other positive attributes in carrier dogs.
Breeders can use results from this test as a tool to select mating pairs to avoid producing affected dogs. About 2% of Tollers carry the CPLS mutation. This mutation accounts for 39% of cleft puppies from North America.
Note: This CPLS test is breed-specific and does not apply to any breed except the Nova Scotia Duck Tolling Retriever.
Normal. No copies of the CLPS mutation are present.
Carrier. 1 copy of the CLPS mutation is present. If carriers are bred together, 25% of offspring are expected to be affected.
Affected. 2 copies of the CLPS mutation.
Wolf, Z.T., Leslie, E.J., Arzi, B., Jayashankar, K., Karmi, N., Jia, Z., Rowland, D.J., Young, A., Safra, N., Sliskovic, S., Murray, J.C., Wade, C.M., & Bannasch, D.L. (2014). A LINE-1 insertion in DLX6 is responsible for cleft palate and mandibular abnormalities in a canine model of Pierre Robin sequence. PLoS Genetics 10(4):e1004257. doi: 10.1371/journal.pgen.1004257