OMIA:001551-9615 : Brachycephaly in Canis lupus familiaris (dog)

In other species: brown trout , domestic cat , pig , taurine cattle , goat , rabbit

Categories: Craniofacial phene

Links to possible relevant human trait(s) and/or gene(s) in OMIM: 112263 (gene) , 607223 (gene) , 125400 (trait)

Mendelian trait/disorder: no

Mode of inheritance: Multifactorial

Considered a defect: yes

Key variant known: yes

Year key variant first reported: 2012

Mapping: By conducting an across-breed GWAS on 25 affected and 31 control dogs from a range of breeds, each genotyped with the Affymetrix Version 2 Custom Canine SNP (comprising 49,663 SNPs), Bannasch et al. (2010) highlighted a region on chromosome CFA1. Fine-mapping reduced the region to 31Kb containing just one gene, THBS2. Sequencing this gene and a neighbouring gene, SMOC-2, failed to reveal a causal mutation. Building on the results of previous mapping studies (e.g. Haworth et al., 2001; Bannasch e al., 2010), Schoenebeck et al. (2012) genotyped 576 dogs from 62 breeds recognised by the American Kennel Club each with a canine SNP chip (61,270 SNPs) and used GWAS analysis based on brachycephaly-dolichocephaly classification to identify five QTL, on CFA1, CFA5, CFA24, CFA32 and CFAX. Marchant et al. (2017) conducted a GWAS, using the 170,000 SNP Illumina CanineHD Whole-Genome Genotyping BeadChip, on "morphometrics of skull isosurfaces derived from 374 pedigree and mixed-breed dogs to dissect the genetics of skull form. Through deconvolution of facial forms, we identified quantitative trait loci that are responsible for canine facial shapes and sizes . . . [, namely] "a highly significant QTL associated with canine brachycephaly on CFA1, as well as numerous other suggestive associations. Focusing on the CFA1 QTL, we defined a 187.7-kb critical interval common to 30 of 37 brachycephalic dogs".

Molecular basis: Extensive whole-genome resequencing of the main QTL on CFA32 (see mapping section above) enabled Schoenebeck et al. (2012) to identify a quantitative trait nucleotide (QTN) for brachycephaly: "a SNP at 8,196,098 that encodes a missense mutation [C/A transversion] in BMP3, changing a phenylalanine to a leucine (BMP3F452L or F452L)". Concentrating on their CFA1 candidate region (see Mapping section), Marchant et al. (2017) "resequenced 28 brachycephalic dogs to approximately 30-fold depth and filtered polymorphisms within the critical interval against variants called in 319 other resequenced canid genomes. Among five variants that were retained, we detected a long interspersed nuclear element (LINE-1) within the SPARC-related modular calcium binding (SMOC2) gene. Transcript analyses revealed alternative splice isoforms that occur in the presence of the LINE-1, causing the incorporation of a premature stop codon after the eighth exon of SMOC2’s canonical 13-exon transcript. SMOC2 mRNA levels are downregulated in a dose-dependent manner with the LINE-1 element". Marchant et al. (2017) report that "SMOC2 disruption affects the facial skeleton in a dose-dependent manner. The size effects of the associated SMOC2 haplotype are profound, accounting for 36% of facial length variation in the dogs we tested." They conclude that "Our data suggest that SMOC2 dysfunction is responsible for canine brachycephaly."

Associated genes:

Symbol Description Species Chr Location OMIA gene details page Other Links
SMOC2 SPARC related modular calcium binding 2 Canis lupus familiaris 1 NC_051805.1 (56009740..56168234) SMOC2 Homologene, Ensembl , NCBI gene
BMP3 bone morphogenetic protein 3 Canis lupus familiaris 32 NC_006614.2 (8172037..8196170) BMP3 Homologene, Ensembl , NCBI gene
DVL2 dishevelled segment polarity protein 2 Canis lupus familiaris 5 NC_051809.1 (32307523..32299943) DVL2 Homologene, Ensembl , NCBI gene


By default, variants are sorted chronologically by year of publication, to provide a historical perspective. Readers can re-sort on any column by clicking on the column header. Click it again to sort in a descending order. To create a multiple-field sort, hold down Shift while clicking on the second, third etc relevant column headers.

WARNING! Inclusion of a variant in this table does not automatically mean that it should be used for DNA testing. Anyone contemplating the use of any of these variants for DNA testing should examine critically the relevant evidence (especially in breeds other than the breed in which the variant was first described). If it is decided to proceed, the location and orientation of the variant sequence should be checked very carefully.

Since October 2021, OMIA includes a semiautomated lift-over pipeline to facilitate updates of genomic positions to a recent reference genome position. These changes to genomic positions are not always reflected in the ‘acknowledgements’ or ‘verbal description’ fields in this table.

OMIA Variant ID Breed(s) Variant Phenotype Gene Allele Type of Variant Source of Genetic Variant Reference Sequence Chr. g. or m. c. or n. p. Verbal Description EVA ID Year Published PubMed ID(s) Acknowledgements
862 Brachycephaly BMP3 missense Naturally occurring variant CanFam3.1 32 g.5231894C>A c.1344C>A p.(F448L) rs851217657 2012 22876193 Variant coordinates obtained from or confirmed by EBI's Some Effect Predictor (VEP) tool
733 Brachycephaly SMOC2 insertion, gross (>20) Naturally occurring variant 1 "a long interspersed nuclear element (LINE-1) within the SPARC-related modular calcium binding (SMOC2) gene" 2017 28552356

Cite this entry

Nicholas, F. W., Tammen, I., & Sydney Informatics Hub. (2024). OMIA:001551-9615: Online Mendelian Inheritance in Animals (OMIA) [dataset].


Note: the references are listed in reverse chronological order (from the most recent year to the earliest year), and alphabetically by first author within a year.

2024 De Decker, S., Rohdin, C., Gutierrez-Quintana, R. :
Vertebral and spinal malformations in small brachycephalic dog breeds: Current knowledge and remaining questions. Vet J 304:S1090-0233(24)00034-0:106095, 2024. Pubmed reference: 38458418. DOI: 10.1016/j.tvjl.2024.106095.
Dehesa-Santos, A., Faria-Teixeira, M.C., Iglesias-Linares, A. :
Skeletal Class III phenotype: Link between animal models and human genetics: A scoping review. J Exp Zool B Mol Dev Evol 342:21-44, 2024. Pubmed reference: 38108095. DOI: 10.1002/jez.b.23230.
Morel, E., Malineau, L., Venet, C., Gaillard, V., Péron, F. :
Prioritization of appearance over health and temperament is detrimental to the welfare of purebred dogs and cats. Animals (Basel) 14:1003, 2024. Pubmed reference: 38612242. DOI: 10.3390/ani14071003.
Moses, W.B., Moses, I.A., Moses, E.A., Moses, P.A. :
Prevalence and classification of congenital thoracic vertebral body abnormalities in neurologically normal brachycephalic 'screw-tail' dog breeds in referral practice in Australia. Aust Vet J , 2024. Pubmed reference: 39032038. DOI: 10.1111/avj.13361.
Niinikoski, I., Himanen, S.L., Tenhunen, M., Aromaa, M., Lilja-Maula, L., Rajamäki, M.M. :
Evaluation of risk factors for sleep-disordered breathing in dogs. J Vet Intern Med 38:1135-1145, 2024. Pubmed reference: 38358051. DOI: 10.1111/jvim.17019.
Rajaei, S.M., Faghihi, H., Zahirinia, F. :
The Shih Tzu eye: Ophthalmic findings of 1000 eyes. Vet Ophthalmol , 2024. Pubmed reference: 38169085. DOI: 10.1111/vop.13182.
Vitor, R.C., de Carvalho Teixeira, J.B., Dos Santos, K.C., Oliveira, G.M.S., Guedes, P.E.B., da Paixão Sevá, A., Gomes Junior, D.C., Veloso, J.F., Carlos, R.S.A. :
Shih-Tzu dogs show alterations in ocular surface homeostasis despite adequate aqueous tear production. Acta Vet Scand 66:3, 2024. Pubmed reference: 38229091. DOI: 10.1186/s13028-024-00724-2.
2023 Andrews, A.L.M.M., Youngman, K.L., Packer, R.M.A., O'Neill, D.G., Kafarnik, C. :
A review of clinical outcomes, owner understanding and satisfaction following medial canthoplasty in brachycephalic dogs in a UK referral setting (2016-2021). Animals (Basel) 13:2032, 2023. Pubmed reference: 37370542. DOI: 10.3390/ani13122032.
Banks, C., Beever, L., Kaye, B., Foo, M., Ter Haar, G., Rutherford, L. :
Influence of extreme brachycephalic conformation on perioperative complications associated with total ear canal ablation and lateral bulla osteotomy in 242 dogs (2010-2020). Vet Surg 52:661-673, 2023. Pubmed reference: 37128636. DOI: 10.1111/vsu.13964.
Brložnik, M., Nemec Svete, A., Erjavec, V., Domanjko Petrič, A. :
Echocardiographic parameters in French Bulldogs, Pugs and Boston Terriers with brachycephalic obstructive airways syndrome. BMC Vet Res 19:49, 2023. Pubmed reference: 36793024. DOI: 10.1186/s12917-023-03600-9.
Dimopoulou, M., Engdahl, K., Ladlow, J., Andersson, G., Hedhammar, Å., Skiöldebrand, E., Ljungvall, I. :
The epidemiology of upper respiratory tract disorders in a population of insured Swedish dogs (2011-2014), and its association to brachycephaly. Sci Rep 13:8765, 2023. Pubmed reference: 37253809. DOI: 10.1038/s41598-023-35466-0.
Erjavec, V., Svete, A.N. :
Thrombocytosis in brachycephalic dogs with brachycephalic obstructive airway syndrome. Vet Med (Praha) 68:57-61, 2023. Pubmed reference: 38332764. DOI: 10.17221/23/2021-VETMED.
Hobi, S., Barrs, V.R., Bęczkowski, P.M. :
Dermatological problems of brachycephalic dogs. Animals (Basel) 13:2016, 2023. Pubmed reference: 37370526. DOI: 10.3390/ani13122016.
Iotchev, I.B., Bognár, Z., Tóth, K., Reicher, V., Kis, A., Kubinyi, E. :
Sleep-physiological correlates of brachycephaly in dogs. Brain Struct Funct 228:2125-2136, 2023. Pubmed reference: 37742302. DOI: 10.1007/s00429-023-02706-y.
McNamara, C. :
Testing for health in brachy dogs. Vet Rec 192:338, 2023. Pubmed reference: 37084190. DOI: 10.1002/vetr.2980.
Meadows, J.R.S., Kidd, J.M., Wang, G.D., Parker, H.G., Schall, P.Z., Bianchi, M., Christmas, M.J., Bougiouri, K., Buckley, R.M., Hitte, C., Nguyen, A.K., Wang, C., Jagannathan, V., Niskanen, J.E., Frantz, L.A.F., Arumilli, M., Hundi, S., Lindblad-Toh, K., Ginja, C., Agustina, K.K., André, C., Boyko, A.R., Davis, B.W., Drögemüller, M., Feng, X.Y., Gkagkavouzis, K., Iliopoulos, G., Harris, A.C., Hytönen, M.K., Kalthoff, D.C., Liu, Y.H., Lymberakis, P., Poulakakis, N., Pires, A.E., Racimo, F., Ramos-Almodovar, F., Savolainen, P., Venetsani, S., Tammen, I., Triantafyllidis, A., vonHoldt, B., Wayne, R.K., Larson, G., Nicholas, F.W., Lohi, H., Leeb, T., Zhang, Y.P., Ostrander, E.A. :
Genome sequencing of 2000 canids by the Dog10K consortium advances the understanding of demography, genome function and architecture. Genome Biol 24:187, 2023. Pubmed reference: 37582787. DOI: 10.1186/s13059-023-03023-7.
Sebbag, L., Sanchez, R.F. :
The pandemic of ocular surface disease in brachycephalic dogs: The brachycephalic ocular syndrome. Vet Ophthalmol 26 Suppl 1:31-46, 2023. Pubmed reference: 36585820. DOI: 10.1111/vop.13054.
Song, A., Phillips, H., Oliveira, C.R., McCoy, A.M. :
CT volumetric analysis permits comparison of tongue size and tongue fat in different canine brachycephalic and mesaticephalic breeds. Vet Radiol Ultrasound 64:429-438, 2023. Pubmed reference: 36787184. DOI: 10.1111/vru.13221.
Souza, C.P., Foss, K.D., Mascarenhas, M.B., Clegg, J.L. :
Otitis media with effusion in two Boston terrier dogs. Vet Med Sci 9:1069-1073, 2023. Pubmed reference: 36723508. DOI: 10.1002/vms3.1092.
Ujfalussy, D.J., Bognár, Z., Molnár, M., Miklósi, Á., Kubinyi, E. :
The difference between two brachycephalic and one mesocephalic dog breeds' problem-solving performance suggests evidence for paedomorphism in behaviour. Sci Rep 13:14284, 2023. Pubmed reference: 37735533. DOI: 10.1038/s41598-023-41229-8.
2022 Appelgrein, C., Hosgood, G., Thompson, M., Coiacetto, F. :
Quantification of gastroesophageal regurgitation in brachycephalic dogs. J Vet Intern Med 36:927-934, 2022. Pubmed reference: 35388526. DOI: 10.1111/jvim.16400.
Estevam, M.V., Beretta, S., Smargiassi, N.F., Apparício, M., Toniollo, G.H., Pereira, G.T. :
Congenital malformations in brachycephalic dogs: A retrospective study. Front Vet Sci 9:981923, 2022. Pubmed reference: 36268051. DOI: 10.3389/fvets.2022.981923.
Kenny, D.D., Freemantle, R., Jeffery, A., Tivers, M.S. :
Impact of an educational intervention on public perception of brachycephalic obstructive airway syndrome in brachycephalic dogs. Vet Rec 190:e1430, 2022. Pubmed reference: 35182434. DOI: 10.1002/vetr.1430.
Mitze, S., Barrs, V.R., Beatty, J.A., Hobi, S., Bęczkowski, P.M. :
Brachycephalic Obstructive Airway Syndrome: much more than a surgical problem. Vet Q 42:213-223, 2022. Pubmed reference: 36342210. DOI: 10.1080/01652176.2022.2145621.
2021 Costa, J., Steinmetz, A., Delgado, E. :
Clinical signs of brachycephalic ocular syndrome in 93 dogs. Ir Vet J 74:3, 2021. Pubmed reference: 33494828. DOI: 10.1186/s13620-021-00183-5.
Geiger, M., Schoenebeck, J.J., Schneider, R.A., Schmidt, M.J., Fischer, M.S., Sánchez-Villagra, M.R. :
Exceptional changes in skeletal anatomy under domestication: The case of brachycephaly. Integr Org Biol 3:obab023, 2021. Pubmed reference: 34409262. DOI: 10.1093/iob/obab023.
Mondino, A., Delucchi, L., Moeser, A., Cerdá-González, S., Vanini, G. :
Sleep disorders in dogs: A pathophysiological and clinical review. Top Companion Anim Med 43:100516, 2021. Pubmed reference: 33556640. DOI: 10.1016/j.tcam.2021.100516.
Niskanen, J.E., Reunanen, V., Salonen, M., Bannasch, D., Lappalainen, A.K., Lohi, H., Hytönen, M.K. :
Canine DVL2 variant contributes to brachycephalic phenotype and caudal vertebral anomalies. Hum Genet 140:1535-1545, 2021. Pubmed reference: 33599851. DOI: 10.1007/s00439-021-02261-8.
O'Neill, D.G., Packer, R.M.A., Francis, P., Church, D.B., Brodbelt, D.C., Pegram, C. :
French Bulldogs differ to other dogs in the UK in propensity for many common disorders: a VetCompass study. Canine Med Genet 8:13, 2021. Pubmed reference: 34911586. DOI: 10.1186/s40575-021-00112-3.
Sahr, S., Dietrich, A., Oechtering, G. :
Evaluating malformations of the lacrimal drainage system in brachycephalic dog breeds: A comparative computed tomography analysis. PLoS One 16:e0257020, 2021. Pubmed reference: 34492067. DOI: 10.1371/journal.pone.0257020.
2020 Smith, S.M., Holt, E., Aguirre, G.D. :
Conjunctival staining with lissamine green as a predictor of tear film deficiency in dogs. Vet Ophthalmol 23:624-631, 2020. Pubmed reference: 32386097. DOI: 10.1111/vop.12762.
Sophocleous, R.A., Sluyter, V., Curtis, B.L., Curtis, S.J., Jurak, L.M., Faulks, M., Spildrejorde, M., Gates, S., Proctor, E.J., Seavers, A., Watson, D., Kuit, T., Dowton, M., Stokes, L., Sluyter, R. :
Association of a P2RX7 gene missense variant with brachycephalic dog breeds. Anim Genet 51:127-131, 2020. Pubmed reference: 31774195. DOI: 10.1111/age.12884.
2019 Dreger, D.L., Hooser, B.N., Hughes, A.M., Ganesan, B., Donner, J., Anderson, H., Holtvoigt, L., Ekenstedt, K.J. :
True Colors: Commercially-acquired morphological genotypes reveal hidden allele variation among dog breeds, informing both trait ancestry and breed potential. PLoS One 14:e0223995, 2019. Pubmed reference: 31658272. DOI: 10.1371/journal.pone.0223995.
Ravn-Mølby, E.M., Sindahl, L., Nielsen, S.S., Bruun, C.S., Sandøe, P., Fredholm, M. :
Breeding French bulldogs so that they breathe well-A long way to go. PLoS One 14:e0226280, 2019. Pubmed reference: 31841527. DOI: 10.1371/journal.pone.0226280.
Riggs, J., Liu, N.C., Sutton, D.R., Sargan, D., Ladlow, J.F. :
Validation of exercise testing and laryngeal auscultation for grading brachycephalic obstructive airway syndrome in pugs, French bulldogs, and English bulldogs by using whole-body barometric plethysmography. Vet Surg 48:488-496, 2019. Pubmed reference: 30666670. DOI: 10.1111/vsu.13159.
Roman, N., Carney, P.C., Fiani, N., Peralta, S. :
Incidence patterns of orofacial clefts in purebred dogs. PLoS One 14:e0224574, 2019. Pubmed reference: 31682628. DOI: 10.1371/journal.pone.0224574.
2018 Fawcett, A., Barrs, V., Awad, M., Child, G., Brunel, L., Mooney, E., Martinez-Taboada, F., McDonald, B., McGreevy, P. :
Consequences and Management of Canine Brachycephaly in Veterinary Practice: Perspectives from Australian Veterinarians and Veterinary Specialists. Animals (Basel) 9:3, 2018. Pubmed reference: 30577619. DOI: 10.3390/ani9010003.
2017 Marchant, T.W., Johnson, E.J., McTeir, L., Johnson, C.I., Gow, A., Liuti, T., Kuehn, D., Svenson, K., Bermingham, M.L., Drögemüller, M., Nussbaumer, M., Davey, M.G., Argyle, D.J., Powell, R.M., Guilherme, S., Lang, J., Ter Haar, G., Leeb, T., Schwarz, T., Mellanby, R.J., Clements, D.N., Schoenebeck, J.J. :
Canine Brachycephaly Is Associated with a Retrotransposon-Mediated Missplicing of SMOC2. Curr Biol 27:1573-1584.e6, 2017. Pubmed reference: 28552356. DOI: 10.1016/j.cub.2017.04.057.
2016 Anon. :
Brachycephaly: an issue for cats as well as dogs. Vet Rec 179:371, 2016. Pubmed reference: 27738208. DOI: 10.1136/vr.i5507.
Vallone, L.V., Enders, A.M., Mohammed, H.O., Ledbetter, E.C. :
In vivo confocal microscopy of brachycephalic dogs with and without superficial corneal pigment. Vet Ophthalmol 20:294-303, 2016. Pubmed reference: 27468727. DOI: 10.1111/vop.12416.
2013 Arnold, T.S., Wittenburg, L.A., Powell, C.C. :
Effect of topical naltrexone 0.3% on corneal sensitivity and tear parameters in normal brachycephalic dogs. Vet Ophthalmol 17:328-33, 2013. Pubmed reference: 23802568. DOI: 10.1111/vop.12079.
Knight, S.M., Radlinsky, M.G., Cornell, K.K., Schmiedt, C.W. :
Postoperative Complications Associated with Caudectomy in Brachycephalic Dogs with Ingrown Tails. J Am Anim Hosp Assoc 49:237-42, 2013. Pubmed reference: 23690492. DOI: 10.5326/JAAHA-MS-5858.
Roedler, F.S., Pohl, S., Oechtering, G.U. :
How does severe brachycephaly affect dog's lives? Results of a structured preoperative owner questionnaire. Vet J 198:606-10, 2013. Pubmed reference: 24176279. DOI: 10.1016/j.tvjl.2013.09.009.
2012 Schoenebeck, J.J., Hutchinson, S.A., Byers, A., Beale, H.C., Carrington, B., Faden, D.L., Rimbault, M., Decker, B., Kidd, J.M., Sood, R., Boyko, A.R., Fondon, J.W., Wayne, R.K., Bustamante, C.D., Ciruna, B., Ostrander, E.A. :
Variation of BMP3 contributes to dog breed skull diversity. PLoS Genet 8:e1002849, 2012. Pubmed reference: 22876193. DOI: 10.1371/journal.pgen.1002849.
2011 Quilez, J., Short, A.D., Martínez, V., Kennedy, L.J., Ollier, W., Sanchez, A., Altet, L., Francino, O. :
A selective sweep of >8 Mb on chromosome 26 in the Boxer genome. BMC Genomics 12:339, 2011. Pubmed reference: 21722374. DOI: 10.1186/1471-2164-12-339.
2010 Bannasch, D., Young, A., Myers, J., Truvé, K., Dickinson, P., Gregg, J., Davis, R., Bongcam-Rudloff, E., Webster, M.T., Lindblad-Toh, K., Pedersen, N. :
Localization of canine brachycephaly using an across breed mapping approach. PLoS One 5:e9632, 2010. Pubmed reference: 20224736. DOI: 10.1371/journal.pone.0009632.
Boyko, A.R., Quignon, P., Li, L., Schoenebeck, J.J., Degenhardt, J.D., Lohmueller, K.E., Zhao, K., Brisbin, A., Parker, H.G., vonHoldt, B.M., Cargill, M., Auton, A., Reynolds, A., Elkahloun, A.G., Castelhano, M., Mosher, D.S., Sutter, N.B., Johnson, G.S., Novembre, J., Hubisz, M.J., Siepel, A., Wayne, R.K., Bustamante, C.D., Ostrander, E.A. :
A simple genetic architecture underlies morphological variation in dogs. PLoS Biol 8:e1000451, 2010. Pubmed reference: 20711490. DOI: 10.1371/journal.pbio.1000451.
Oechtering, G.U., Schlüter, C., Lippert, J.P. :
[Brachycephaly in dog and cat: a "human induced" obstruction of the upper airways]. Pneumologie 64:450-2, 2010. Pubmed reference: 20632241. DOI: 10.1055/s-0030-1255513.
2009 Hünemeier, T., Salzano, F.M., Bortolini, M.C. :
TCOF1 T/Ser variant and brachycephaly in dogs. Anim Genet 40:357-8, 2009. Pubmed reference: 19220226. DOI: 10.1111/j.1365-2052.2008.01838.x.
2001 Haworth, KE., Islam, I., Breen, M., Putt, W., Makrinou, E., Binns, M., Hopkinson, D., Edwards, Y. :
Canine TCOF1; cloning, chromosome assignment and genetic analysis in dogs with different head types. Mamm Genome 12:622-9, 2001. Pubmed reference: 11471057. DOI: 10.1007/s00335-001-3011-0.

Edit History

  • Created by Frank Nicholas on 28 Feb 2011
  • Changed by Frank Nicholas on 19 Dec 2012
  • Changed by Frank Nicholas on 21 May 2013
  • Changed by Frank Nicholas on 05 Jul 2017
  • Changed by Imke Tammen2 on 28 Aug 2021
  • Changed by Imke Tammen2 on 18 Apr 2023
  • Changed by Imke Tammen2 on 09 Apr 2024