Domestic dog breeds exhibit remarkable morphological variations that result from centuries of artificial selection and breeding. Identifying the genetic changes that contribute to these variations could provide critical insights into the molecular basis of tissue and organismal morphogenesis. Bulldogs, French Bulldogs and Boston Terriers share many morphological and disease-predisposition traits, including brachycephalic skull morphology, widely set eyes and short stature. Unlike other brachycephalic dogs, these breeds also exhibit vertebral malformations that result in a truncated, kinked tail (screw tail). Whole genome sequencing of 100 dogs from 21 breeds identified 12.4 million bi-allelic variants that met inclusion criteria. Whole Genome Association of these variants with the breed defining phenotype of screw tail was performed using 10 cases and 84 controls and identified a frameshift mutation in the WNT pathway gene DISHEVELLED 2 (DVL2) (Chr5: 32195043_32195044del, p = 4.37 X 10−37) as the most strongly associated variant in the canine genome. This DVL2 variant was fixed in Bulldogs and French Bulldogs and had a high allele frequency (0.94) in Boston Terriers. The DVL2 variant segregated with thoracic and caudal vertebral column malformations in a recessive manner with incomplete and variable penetrance for thoracic vertebral malformations between different breeds. Importantly, analogous frameshift mutations in the human DVL1 and DVL3 genes cause Robinow syndrome, a congenital disorder characterized by similar craniofacial, limb and vertebral malformations. Analysis of the canine DVL2 variant protein showed that its ability to undergo WNT-induced phosphorylation is reduced, suggesting that altered WNT signaling may contribute to the Robinow-like syndrome in the screwtail breeds.

OBJECTIVE To evaluate the diagnostic yield of dental radiography (Rad method) and cone-beam CT (CBCT) methods for the identification of 31 predefined dental disorders in brachycephalic dogs. ANIMALS 19 client-owned brachycephalic dogs admitted for evaluation and treatment of dental disease. PROCEDURES 31 predefined dental disorders were evaluated separately and scored by use of dental radiography and 3 CBCT software modules (serial CBCT slices and custom cross sections, tridimensional rendering, and reconstructed panoramic views). A qualitative scoring system was used. Dental disorders were grouped into 10 categories for statistical analysis. Point of reference for presence or absence of a dental disorder was determined as the method that could be used to clearly identify the disorder as being present. Accuracy, sensitivity, specificity, and positive and negative predictive values were calculated with the McNemar χ test of marginal homogeneity of paired data. RESULTS When all 3 CBCT methods were used in combination, the diagnostic yield of CBCT was significantly higher than that of dental radiography for 4 of 10 categories (abnormal eruption, abnormally shaped roots, periodontitis, and tooth resorption) and higher, although not significantly so, for all categories, except for 1 (loss of tooth integrity). CONCLUSIONS AND CLINICAL RELEVANCE CBCT provided more detailed information than did dental radiography. Therefore, CBCT would be better suited for use in diagnosing dental disorders in brachycephalic dogs.

Skulls from 392 grey wolves (Canis lupus) were examined macroscopically according to predefined criteria. Two hundred and seven skulls were included in this study, comprised of 124 young adults (59.9%) and 83 adults (40.1%); of these, 65 (31.4%) specimens were from male wolves and 104 (50.3%) were from females, with 38 (18.4%) of unknown sex. Out of 8,694 possible teeth, 8,339 (95.9%) were present for evaluation. Fifty-five teeth (15.5%) were absent congenitally, 30 (8.5%) were lost during life and 270 (76.1%) were lost artefactually post mortem. Skeletal or dental malocclusion was present in 37 specimens (17.9%), with level bite being the most commonly encountered malocclusion. Enamel hypoplasia was present in five skulls (2.4%), affecting eight teeth (0.1%) in total. An abnormal number of roots was found on 23 teeth (0.3%) on 13 skulls (6.3%). Persistent deciduous teeth occurred in two (1.0%) specimens, affecting one (0.01%) tooth each. Fenestration or dehiscence was found associated with 203 teeth (2.4%) in 72 skulls (34.8%). Periodontitis was noted on 115 skulls (55.6%) and 1,000 teeth (11.5%), affecting significantly more adults (n = 63, 75.0%) than young adults (n = 52, 41.9%; P <0.0001). One hundred and sixty-one skulls (77.8%) showed signs of endodontal disease, including attrition or abrasion on 144 skulls (69.6%) and 2,522 teeth (30.2%) and 424 fractured teeth (5.1%) on 103 skulls (49.8%). Both lesions affected significantly more adults than young adults. Overt periapical disease was associated with six teeth (0.1%) distributed across five skulls (2.4%). A carious lesion was present on one tooth (0.01%) of one specimen (0.5%). Lesions consistent with temporomandibular joint (TMJ) osteoarthritis were found in 24 specimens (11.6%), affecting 38 joints (9.2%). Trauma to the skull, such as bite marks, bullet holes or blunt trauma, was noted in 44 skulls (21.2%). The grey wolf and the domestic dog (Canis lupus familiaris) share common dental diseases; however, the proportion and severity may vary. Although the clinical significance of dental and TMJ pathology in the grey wolf remains unknown, based on the impact of these disorders on the domestic dog, the occurrence and severity of these lesions are likely to play an important role in the morbidity and mortality of this wild canid species.