Nova Scotia Duck Tolling Retriever ONLY


Cleft palate is a hole (cleft) in the roof of the mouth (palate) that occurs during development of the puppy. Puppies are born with cleft palate. Cleft Lip is a split in the lip and can occur on one or both sides of the mouth. Syndactyly is fusion of the middle two digits of the feet. The NSDTR breed has multiple genetic causes of cleft palate. A mutation test is already available for CP1 in the NSDTR which causes cleft palate. We have recently identified the mutation that causes a second form of cleft lip and cleft palate called CLPS. This mutation test is BREED specific and does not apply to any breed except the NSDTR. If you have a puppy with cleft palate from another breed and wish to participate in the identification of the genes responsible please contact the Bannasch Laboratory at the University of California at Davis (


Scientists from the Bannasch Laboratory at the University of California, Davis and the Wade Laboratory from the University of Sydney have discovered the genetic cause of a second form of cleft palate in the Nova Scotia Duck Tolling Retriever. Dogs with this form of cleft palate have an inactivating mutation in a gene important in normal development. The mutation is not present in any other breeds of dogs based on testing over 80 breeds and over 300 individual animals.

The Mode of Inheritance

CLPS is inherited as an autosomal recessive disease meaning that affected puppies inherited two mutant copies of this gene, one from each of their parents. 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 can have syndactyly but don’t always. One case had a cleft nose and syndactyly. A summary of the variation in the clinical presentation of two copies of the CLPS mutations is shown below. 

The Test Results

CLPS N/N: This dog has two normal copies of CLPS and can only transmit the normal gene to its offspring. This dog will not produce puppies with cleft palate, cleft lip or syndactyly caused by the CLPS mutation. In the NSDTR there are other inherited forms of cleft palate. This test does not give any information about those other forms of cleft palate.
CLPS N/A: This dog has one mutant (abnormal) and one normal copy of the gene, and is classified as a Carrier. This dog can transmit the abnormal copy of the gene to its puppies and therefore if bred to another carrier of CLPS, can produce puppies with cleft palate, cleft lip or syndactyly.
CLPS A/A: This dog has two mutant (abnormal) copies of CLPS and is homozygous A/A. No dogs have ever been identified that were homozygous for CLPS that did not have cleft palate, cleft lip or syndactyly in over 500 dogs tested. We offer testing of puppies with cleft palate at no cost in order to determine if the puppy has the CLPS form of cleft or another form. Please contact Zena Wolf for more information at These tests will be performed on a research basis.


CLPS is inherited as an autosomal recessive disease meaning that animals that are N/A are normal but can produce affected puppies if bred to another carrier (N/A). There are ~ 2% of Tollers that carry CLPS (N/A) at the time the test was released; however, this number can change with each generation. We have received 36 samples from cleft puppies from North America in the NSDTR and 14 of those were caused by CLPS. Dogs that are carriers (N/A) are completely normal themselves 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. Puppies affected with cleft palate will be tested at no charge. Please contact Zena Wolf for more details (

Breeder Guidelines

Owners with dogs testing as Carriers (CLPS N/A) should understand that their dogs can produce puppies with cleft palate, cleft lip, syndactyly or a combination of these birth defects if bred to other carriers. In addition, all NSDTR breeders should understand that this test is specific for the mutation identified to cause the CLPS form of cleft palate. At the time that this test was released, approximately 2% of Tollers were identified as carriers of CLPS N/A; however, the number of carriers can change with each generation. As of March 2012, we have received 36 samples from North American NSDTR puppies with cleft palate, 14 of which had two mutant (CLPS A/A) copies of CLPS.

If two carriers of CLPS are bred to each other, 25% of the puppies will likely have a phenotype caused by CLPS. If a carrier is bred to a normal dog, then no CLPS puppies will be produced.

We recommend that breeders take into consideration the CLPS test results as they plan their breeding programs; however, they should not over-emphasize the test results. Instead, the test result should be one factor among many in a balanced breeding program.

Order DNA Test

Tests are ordered online through the secure area of the OFA website. Payment is accepted by credit card (MasterCard and VISA). The OFA administers all order handling. Upon receipt of an order, the OFA will send out the test kit which will include a Foam-Tipped Applicator card for DNA sample collection, along with sample collection instructions. Using the FTA card technology, owners can safely collect DNA samples at home. The collection process is non-invasive, and no veterinary appointment is necessary.

Samples are then sent to the University of Missouri College of Veterinary Medicine where the samples will be processed by the Small Animal Molecular Genetics Lab. Results will be forwarded to the OFA, and the OFA will issue the resulting report to the owner.

The fee for each test includes the test kit, laboratory processing, and subsequent registration in the OFA databases.