Rapport of TheTibetan Terrier World Congress 2022 in France

Af Dr Mike Tempest (Mikudi TTs)

The Congress itself

This was the 16th TT World Congress and was held on Sunday 25th September 2022 in France for the first time. The venue was the Clermotel Hotel in Agnetz in the Oise Region of Northern France. There had been considerable difficulties in arranging this congress as it was originally scheduled for 2020, but it had to be postponed because of Covid. An attempt was made to hold it in 2021 but again Covid intervened. Finally, it was ‘third time lucky’ for 2022.

Fourteen counties were represented by 51 participants. There were 14 from France; 8 from the UK; 5 from Denmark; 4 from Belgium; 3 each from Slovakia and the USA; 2 each from Germany, Ireland, Lithuania, the Netherlands, New Zealand and Sweden; and 1 each from Canada and Switzerland.  

There were two sessions of speakers. In the morning session there was an excellent programme of French speakers, eminent authorities in their own subject, dealing with Eye Diseases, Hip Dysplasia, Itching/Dermatitis, and Genomics. The afternoon session was for TT speakers: Mark James and Glenn Davies spoke about their passion, knowledge and understanding of TTs; Mike Tempest provided a review of the important 2019 scientific paper on the genetics of our breed; finally, there was a Q&A session with a panel of experienced TT breeders and exhibitors.

Eye disease – hereditary or not?

This talk was presented by Dr Giles Chaudieu, an Ophthalmologist, who as well as being an eye examiner also advises the Scientific Committee of the French Kennel Club. He listed the questions to be asked when an ocular disease is first suspected: (1) Is the frequency in a breed greater than in other breeds; (2) Is the frequency in the breed increasing; (3) Is the frequency greater in related dogs in the breed; (4) Is the age of onset and the course of progression predictable; and (5) Are the characteristic clinical signs identical to a disease proven to be inherited in another breed?

He then went through to show how these criteria were met when PLL and PRA was suspected and stressed that it is important that there are published reports in the scientific literature that provide evidence of inheritance. Two other eye conditions which have been observed in TTs were detailed – Persistent Pupillary Membrane (PPM) and Persistent Hyperplastic Tunica Vasculosa Lentis/Persistent Hyperplastic Primary Vitreous (PHTVL/PHPV), but there are no scientific publications, previous evidence or genetic testing in a representative population of TTs. He gave incidence figures for all forms of PRA in TTs in France as 1.5% of 8,017 TTs examined from 1991 to 2015; and 0.2% of 1,274 TTs examined from 2015 to 2019. PLL became a listed condition for TTs when 50 affected dogs were identified in a 5-year period.

Dr Chaudieu concluded by emphasising that diagnosis under a reliable scheme, a large clinical follow-up and genetic testing are needed to evaluate the situation in a breed.

Normal hips – what are the criteria?

This talk was given by Professor Jean Pierre Genevois, Orthopaedic Expert of the FCI Scientific Commission. He explained that the hip joint is the joint that enables the biggest breadth of movement: extension/flexion, abduction/adduction, external rotation/internal rotation. He then defined a normal hip as a stable one that apart from these movements, no other movement is possible.

 For the dynamic and functional aspects of the hip to be optimal, the joint should have a number of anatomical characteristics to ensure its stability. The acetabulum (socket) has to be deep enough to cover a significant portion of the femoral head (the head of the thigh bone). The stability is also made possible by ‘joint restraint’ proved by a ligament linking the femoral head to the bottom of the acetabulum. This round ligament plays an important role during skeletal development but its role in the adult dog is limited to the provision of shock absorption. In adults, joint stability is ensured by the joint capsule, which is a fibrous membrane attached around the acetabulum and onto the femoral neck. This is the most important element for passive stability. Finally active stabilisation of the hip joint benefits from its powerful muscular cover provided by three gluteal muscles.

These different functional criteria are detected in the adult dog by radiographic examination (x-rays). (In answer to a question these criteria cannot be detected by an ultrasonic sound scan). Any deviation from the above criteria will cause some instability of the hip joint to varying degrees, disrupting the biomechanical processes from the normal functioning of the hip. This is what hip dysplasia is.

Itching: understanding, treating and preventing it

This talk was by Professor Dr Daniel Combarros, a dermatologist at the Veterinary School of Toulouse. It was a most useful presentation because itching seems to have become a problem in TTs and we have not previously had much information about it. It is for this reason that this ‘summary’ of the paper may be more than for the other talks.

Itching is caused by atopic dermatitis, which is defined as a chronic inflammatory pruritic skin condition, with characteristic features. It is in effect an allergic condition which is complex and multifactorial. It has a genetic base which causes the skin barrier to be defective which in turn causes the immune system to overact in producing antibodies against environmental allergens. Once the skin is inflamed, the dog scratches himself and aggravates the skin condition. The skin gets infected, inflammation increases, and the itch worsens creating a vicious circle of skin damage.

Typically, the disease manifests before three years of age, with itching, scratching, licking and biting as the main signs. This progressively leads to skin redness, loss of hair, crust formation, malodour and otitis (ear inflammation). The itch is located in the extremities – between the toes, in the crutch (inguinal region), lips, eyelids and ear.

It is known that genetics plays an important role because some breeds are predisposed to this disease – Labradors, Golden Retrievers, German Shepherd Dogs, Bulldogs, Boxers, Shih Tzus, and all kinds of terriers especially West Highland Whites and Jack Russells. However no single gene is involved but a multitude (polygenic). Unfortunately, very few genetic studies have been done, and no genetic study concerning the disease in TTs. Prof Combarros said that because there is no unique gene involved, it is probable that a genetic test will never exist for diagnosing this disease (MT’s comment: this is like HD, but because the genome of the dog has been mapped, and genetic science is progressing rapidly, it may be possible in the future to determine the combinations of genes that cause polygenic diseases). However, we do know that excluding atopic dogs from breeding will decrease the prevalence of the disease.

In the meantime, we must recognise that there is no cure for the disease, and we must rely on treatment, which is multi-model and must be adapted to each case. The main treatments are: (1) Shampoos that are adapted to reduce allergen presence on the skin, restore the skin barrier, moisturize it and prevent secondary infection; (2) constant and correct flea prevention all year round as parasites will worsen the condition; (3) finding the implicated allergens and de-sensitizing the skin to them; (4) symptomatic medical control of the itch cycle to provide some comfort to the dog.

Genomics as an aid to selection

This paper was given by Fleur-Marie Missam, a Deputy Director of the French Kennel Club (FKC, or SCC: Société Centrale Canine in French) and manager if the FKC Health and Genetic Resources. She said that genetic tests are nowadays an essential tool for the selection of breeding stock. These tests can identify parentage and the genetic status of potential parents for monogenetic disease conditions. Elaborated by the Scientific Committee of the FKC, in collaboration with the French Breed Club (CCTF: Club des Chiens Tibétains de France), the genomic pack for TTs is for five genetic diseases and eight coat colours. The individual results returned to breeders are a very efficient selection tool, especially for the detection of carriers in order to avoid matings between carriers.

The next step with the genomic results is the study of genetic diversity of breed populations. This can be determined from the genomic homozygosity results. Instead of having the inbreeding coefficients calculated from pedigree information, the genetic markers will give the level of genomic inbreeding in each individual, meaning that individual puppies in a litter will have different genomic inbreeding coefficients because they have inherited different chromosome combinations and therefore different alleles (gene variants). The slides showed tables for this indicating for a sample of genes which two alleles were present (homozygous means two both the same, heterozygous mean two different alleles). It was quoted that French TTs have a homozygosity rate of 36%, meaning that 36% of the genes so far sampled are homozygous, and therefore 64% are heterozygous.

(MT’s comment: genomic inbreeding calculations will include all the genes, including those that make a TT a TT, and this will produce extremely high figures which will be damaging to breeds in the hands of our critics. Genomic inbreeding means the conventional definition of inbreeding, that it only affect those genes for which various alternatives exist, will be disregarded, as the genes that make a TT a TT will be included in the genomic calculation, yet they are identical genes in each dog that were fixed in the breed at its origin, and they are not affected, nor do they contribute to inbreeding as geneticists understand it).

The results of DNA tests in France were presented, [and although no indication over what the period of time was for these results MT suspects they were over all-time]. The results were: for NCL  127 tests, 94% clear, 5% carriers, 1% affected; for PLL 127 tests, 81% clear, 19% carriers, 0% affected; for PRA3, 115 tests, 100% clear; for RCD4 123 tests, 71% clear, 28% carriers, 1% affected. The official results for each dog are written on each dog’s pedigree along with the results for three generations; and on the French on-line database called LOF Select [which is the equivalent of myKC]. (LOF stands for Livres des Origines Francais which translates to Documents of Origin i.e., pedigrees). The speaker made a plea to be able to compare results from different countries in order to have an overview of these diseases in the breed’s world population.

Perspective On TTs – A passion, knowledge and understanding

Mark James and Glenn Davies (Waterley TTs, UK) gave this presentation. They praised World Congresses for enabling breed enthusiasts to come together to share experiences, thoughts for the future, differing views on the breed, passionately held yet openly discussed and debated; and to take these back to the respective countries for filtering down to enthusiastic breeders, owners, exhibitors and breed clubs. They analysed the features that make a good World Congress – good, authoritative and TT experienced speakers; time for discussions, conversations and chatting in a relaxed environment; a breed club show; light-hearted moments with an auction of TT paraphernalia; a Congress banquet; and great camaraderie. It is the people who attend Congresses that make them a success as the more and more they become involved with owning, breeding, exhibiting or any aspect of TTs, the more they strive for information, knowledge and a community of like-minded people. Long may this continue.

The Population Structure and Genetic History of TTs

Dr Mike Tempest (Mikudi TTs, UK) provided a review of a scientific study on this subject by genetic scientists at the Universities of Zagreb (Croatia) and Ljubljana (Slovenia) which was published in 2019. The review was intended for the Congress originally scheduled for 2020 but which had to be postponed due to Covid. Nevertheless, this was still a topical and important issue.

The study had four main objectives: (1) to test if the original TT belonged to a group of ancient dog breeds of Asian origin; (2) to test if the TT belonged to the group of terrier breeds; (3) to compare the current Western and Native populations; and (4) to compare the ‘Lamleh’ and ‘Luneville’ lineages. It did this by DNA sampling of 64 dogs of the so-called Lamleh and Luneville lineages, collectively known as the Western Population, the current Native population in Tibet, and backcrosses of the Natïve population with Lamleh. It then employed several standard genetic analytical techniques, mainly those known as the ‘Neighbor-joining Tree’ which computes genetic distances between 161 dog breeds/strains, and the ’NeighborNet’ which computes the phylogenetic relationships between 27 dog breeds and the grey wolf (i.e., the phylum/species relationship between wolves and dogs).

Results from the ‘Neighbor-joining Tree’ showed TTs are in two ‘clusters: the Native Population and the first cross of Native with Lamleh are grouped with the ‘Cluster of Ancient Asian Dog Breeds’, and the Lamleh and Luneville Western Population together with the second and third backcrosses of Native to Lamleh are grouped in a ‘Tibetan Companion Dog Cluster’ which includes Tibetan Spaniels, Shih Tzus, Lhasa Apsos and Pekingese, yet all still with the Ancient Asian Dog cluster. Most importantly the study found that there is no genetic distance between the Lamleh and Luneville lineages, and that there was only a small genetic distance between the current Native and Western populations.

Results from the ’NeighborNet’ clearly showed that the Terrier breeds formed a group on the opposite side of the network separate from all the TT groups, which confirmed that TTs are not Terriers. It also showed that the TT Native branch is closer to the Grey Wolf than any other breed, confirming that the TT is a very ancient breed.

However, it was also found that the current Western population showed some sporadic contacts may have occurred with some Terrier breeds during the last century, AND that the edges of the branches between native TTs and Tibetan Spaniels, Shih Tzus, Lhasa Apsos and Pekingese indicated that hybridization events between them may have occurred from random street dog matings.

The conclusions to the objectives were: (1) Yes the TT belongs to a group of ancient dog breeds of Asian origin; (2) No, the TT does not belong to the group of terrier breeds; (3) Yes, the current Western and Native populations are slightly different; and (4) No, there are no genetic differences between the ‘Lamleh’ and ‘Luneville’ lineages. The implication of this for the breed is that we must recognise that we are genetically one breed.