Cleft Lip Palate (Nova Scotia Duck Tolling Retriever Type)

Test Overview:

Cleft palate (CP) is a developmental defect of the hard and/or soft palates, resulting in a hole (fistula) between the oral and nasal cavities.  This congenital (i.e. present at the time of birth) defect is seen more commonly in pure breed dogs and a number of breeds are predisposed to this condition.  Some may be prone to developing CP as a defect seen on its own, while others may develop the condition as part of a syndrome of abnormalities.  In the Nova Scotia duck tolling retriever CP is seen in conjunction with a shortened mandible and an abnormal positioning of the tongue (designated CP1 cleft palate). Cleft palate is a complex condition involving genetic and environmental elements, and is thought to be a common reason for the loss of puppies in the first three days of life.  In dogs, fusion of the bones and other tissues that form the palate generally occurs between days 25 to 33 of the gestation period and this is when injury to the foetus may result in CP.  There are many elements that have been shown to be capable of causing this, including drugs such as aspirin or cortisone, too much vitamin A, certain antibiotic and antifungal agents, as well as some viral infections.  Folic acid has been shown to reduce the rate of cleft palate in some dog breeds, but note the rate of CP after treatment remained around 4% in both the Boston terrier and French bulldog, hence it did not eliminate the condition. Cleft palate results in pups not being able to suckle properly due to a lack of suction.  This results in poor growth and in severe cases death due to starvation.  Milk may be seen to dribble from the nostrils and pups may sneeze or cough.  Aspiration pneumonia is quite common and may also lead to death.  Treatment is recommended as being placement of a feeding tube and surgical repair of the cleft at the age of 6 - weeks.  Affected animals should not be used for breeding.  It should be noted that currently many affected pups probably die or are euthanised, and the true incidence of the condition in many breeds is unknown.


Ontogeny / ontogenesis (or simply developmental) - Developmental (Diseases associated with in-utero development)


ADAM metallopeptidase with thrombospondin type 1 motif 20 (ADAMTS20) on chromosome 27

Variant Detected:

Nucleotide Deletion c.1360-1361delAA p.Lys453Ilefs*3


Low-Moderate. This disease can cause some discomfort and/or dysfunction in the affected animal. It does not generally affect life expectancy.

Mode of Inheritance:

Autosomal Recessive

Research Citation(s):

Wolf ZT, et al. Genome-wide association studies in dogs and humans identify ADAMTS20 as a risk variant for cleft lip and palate. (2015) PLoS Genet, 11(3): e1005059

Associated Breed(s):

Mixed Breed, Nova Scotia Duck Tolling Retriever ,