NTUAS

Summary

Norwich Terrier Upper Airway Syndrome (NTUAS) is a term used to describe respiratory problems of the upper airway in Norwich terriers. NTUAS is considered the number one health problem facing Norwich terriers. Signs include noisy breathing and exercise intolerance - especially in hot and humid weather - and snoring when sleeping. Almost all Norwich terriers have NTUAS to some degree or other. Most Norwich with NTUAS can cope, some require surgical relief as NTUAS has been described as "like breathing through a straw".

Details

Originally thought to be caused by an elongated soft palate and the same as Brachycephalic Obstructive Airway Syndrome [1], current thinking is that NTUAS is different, unique to Norwich, and the soft palate is not involved. A grading scheme for the Norwich upper airway was proposed in 2009 in a University of Berne (Switzerland) Ph.D. dissertation [2]. Unfortunately this Swiss grading scheme was never published and is only done in Europe. Further documentation of an upper airway problem in Norwich terriers was done in 2014 [3].

A 2015-2019 research study at Michigan State University under Dr Bryden Stanley (with help from researchers at UC-Davis, Texas A&M, and Penn) reproduced and extended NTUAS research, including development of a grading scheme for the upper airway (often referred to as the American grading scheme, Dr. Stanley's grading scheme, or an NTUAS scoring). Some talks by Dr. Stanley on the subject of NTUAS have been recorded:

While Dr. Stanley's research has not (yet) been published, the scoring scheme developed by Dr. Stanley and her research collaborators is available. Many vets are able to perform a NTUAS scoring. Certainly any board-certified veterinary surgeon can do a NTUAS scoring. Norwich owners are finding that sometimes their local vet will do a NTUAS scoring as part of a dental cleaning. (NTUAS scoring requires light anesthesia.) Some Norwich owners and breeders are making the NTUAS score sheets on their dogs publically available.

In 2019 European researchers published a paper reporting on an association between a mutation in the ADAMTS3 gene and Norwich Terrier Upper Airway Syndrome (NTUAS) [4]. While this is almost certainly not the entire story with regards to the genetics of UAS, it does give breeders a DNA tool to use to try to breed away from this problem. Orivet is the only lab currently offering this DNA test.

Last updated 20231215.

References

[1] Brachycephalic Syndrome in Dogs, D.A.Koch, et al., Compendium on Continuing Education for the Practising Veterinarian, Vol. 25, No. 1, Jan 2003.

[2] Das Obere Luftweg-Syndrom beim Norwich-Terrier: Beschreibung der Erkrankung und der Untersuchungsmethoden, sowie Entwicklung und Evaluierung eines zuchthygienisch nutzbaren Scoring-Schemas., Martina Ruchti, 2009

[3] Upper Airway Obstruction in Norwich Terriers: 16 Cases, L.R. Johnson, et al., Journal of Veterinary Internal Medicine, Volume 27 Issue 6, pp. 1409-1415, 30 Sep 2013.

[4] An ADAMTS3 missense variant is associated with Norwich Terrier upper airway syndrome, Marchant et al., PLoS Genetics, 2019.