Clemson Canine Genetics

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Dental Abnormalities

Lance Canines

Lance canines are caused by a rostral displacement of the upper canine tooth and are named for their lance or spear-like appearance. In some dogs the lance canine can cause improper shutting of the mouth, ulceration, and/or periodontal disease. This dental abnormality is seen almost exclusively in the Shetland sheepdog.

(A) The upper canine tooth of an affected dog compared to (B) a Sheltie with normal dentition

We discovered that lance canines are associated with smaller body size in the Shetland sheepdog and identified a region on chromosome 9 that is associated with reduced body size and lance canine risk in the breed. Click here to read our publication describing these findings. 


Click here to read an article written to explain the findings of this research and how the genetic test could be used by breeders.


A genetic test for MCM/lance canines is currently being offered by VetGen.

Missing Third Incisor

Dogs with missing third incisors are lacking the upper deciduous (baby) third incisor, permanent (adult) third incisor, or both. Often when a dog is missing the permanent tooth, there is delayed eruption of the deciduous incisor and the deciduous incisor is retained throughout the dog’s adult life. This dental abnormality is seen almost exclusively in the Shetland sheepdog, suggesting a heritable component.

A Sheltie that is missing its permanent third incisor but has a retained deciduous incisor, indicated by the arrow.

Missing Premolars/Molars

Missing premolars and/or molars are most frequently reported in smaller dog breeds, such as the Shetland sheepdog. This abnormality is separate from the missing third incisors.

(A) A Sheltie missing the upper second premolar and lower fourth premolar, indicated by the arrows, compared to (B) a Sheltie with normal dentition.

Missing third incisors and missing premolars/molars are developmental dental abnormalities prevalent in the Shetland sheepdog. The goal of our current studies is to identify genetic markers associated with each type of missing teeth to develop genetic tests for breeders to use as tools to selectively breed away from these anomalies while optimizing genetic diversity in the breed.

We are currently collecting DNA from Shetland sheepdogs that are affected with missing third incisors or missing premolars/molars.

For more information, please contact Sydney Abrams at srabram@g.clemson.edu