OMIA:000272-9615 : Dermoid sinus in Canis lupus familiaris (dog)

In other species: domestic cat , taurine cattle

Categories: Integument (skin) phene

Mendelian trait/disorder: yes

Considered a defect: yes

Key variant known: yes

Year key variant first reported: 2007

Cross-species summary: Also called dermal sinus tract; neural tube defect (NTD) resulting in failed separation of the neural tube from the skin ectoderm

Species-specific name: ridge; hair ridge; dermoid cyst

Species-specific description: Dermoid sinuses and cysts have been described in dogs from several breeds. Hillbertz and Andersson (2006) reported that in the Rhodesian ridgeback population, dogs with the autosomal dominant ridge are predisposed to dermoid sinuses. Salmon Hillbertz et al. (2007) identified the causative mutation for the autosomal dominant dorsal hair ridge in Rhodesian and Thai Ridgeback dogs and proposed that "the mutation predisposes to dermoid sinus with low penetrance in duplication heterozygotes and with high penetrance in homozygotes."

Inheritance: "[T]he ridge trait [in Rhodesian Ridgeback dogs] is inherited in a dominant fashion; thus a single copy of this duplication results in appearance of a ridge, and dogs with two copies of the duplication are indistinguishable from dogs with one copy" (Waldo and Diaz, 2015) Homozygotes for the Ridge allele are more likely to also have a dermoid sinus (Salmon Hillbertz et al., 2007). Inheritance of dermoid sinuses in other breeds is less well documented.

Mapping: In a landmark study, Karlsson et al. (2007) mapped the hair-ridge locus to a 750kb region on chromosome CFA18 via one of the first Genome-Wide Association Studies (GWAS) using 27,000 SNPs on just "9 ridgeless Rhodesian ridgebacks and 12 ridged controls".

Molecular basis: The 750kb candidate region on CFA18 identified by Karlsson et al. (2007) (see Mapping section) contains five genes, three of which are fibroblast growth factor (FGF) genes that in chickens have an integral role in embryonic development. In an accompanying paper in the same issue of Nature Genetics, Salmon Hillbertz et al. (2007) reported that the hair-ridge phenotype (which predisposes to dermoid sinus) is due to a large duplication encompassing all three FGF genes (FGF3, FGF4, FGF19) and another gene ORAOV1.

Genetic testing: Waldo and Diaz (2015) reported a useful diagnostic test for the duplication causing the ridge allele detailed above. While homozygotes and heterozygotes for the duplication (Ridge allele) have identical ridge appearance (characteristic of ridged breeds), homozygotes for the Ridge allele are more likely to also have a dermoid sinus (Salmon Hillbertz et al., 2007).

Breeds: Chow Chow (Dog) (VBO_0200361), Dachshund (Dog) (VBO_0200406), French Bulldog (Dog) (VBO_0201455), Italian Cane Corso (Dog) (VBO_0200712), Rhodesian Ridgeback (Dog) (VBO_0201135), Siberian Husky (Dog) (VBO_0201233), Thai Ridgeback (Dog) (VBO_0201348), Yorkshire Terrier (Dog) (VBO_0201448).
Breeds in which the phene has been documented. (If a likely causal variant has been documented for the phene, see the variant table breeds in which the variant has been reported).

Associated genes:

Symbol Description Species Chr Location OMIA gene details page Other Links
FGF4 retrogene on CFA12 fibroblast growth factor 4 Canis lupus familiaris 18 NC_051822.1 (49090454..49093840) FGF4 retrogene on CFA12 Homologene, Ensembl , NCBI gene
FGF19 fibroblast growth factor 19 Canis lupus familiaris 18 NC_051822.1 (49142011..49147073) FGF19 Homologene, Ensembl , NCBI gene
FGF3 fibroblast growth factor 3 Canis lupus familiaris 18 NC_051822.1 (49057796..49065400) FGF3 Homologene, Ensembl , NCBI gene
ORAOV1 oral cancer overexpressed 1 Canis lupus familiaris 18 NC_051822.1 (49159378..49167844) ORAOV1 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
929 Rhodesian Ridgeback (Dog) Thai Ridgeback (Dog) Ridge & dermoid sinus FGF3 Ridge allele duplication Naturally occurring variant CanFam3.1 18 g.48372578_48505893dup133316 A large ~133,000 bp duplication on chromosome 18, encompassing three FGF genes (FGF3, FGF4, FGF19) and another gene ORAOV1. There is an additional single T inserted between the two copies of the duplication. This is not indicated in the genomic variant designation. 2007 17906623

Cite this entry

Nicholas, F. W., Tammen, I., & Sydney Informatics Hub. (2024). OMIA:000272-9615: 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.

2023 Torres, R., Giovanella, C., Sessums, K. :
Type I and type IV dermoid sinus with associated cervical spina bifida in a Labrador Retriever mixed breed dog. Vet Med Sci , 2023. Pubmed reference: 37965842. DOI: 10.1002/vms3.1319.
2022 Distl, O. :
Prevalence and segregation analysis of dermoid sinus in Rhodesian Ridgebacks. Vet J 280:105803, 2022. Pubmed reference: 35150843. DOI: 10.1016/j.tvjl.2022.105803.
Marín-García, P.J., Llobat, L. :
Inheritance of monogenic hereditary skin disease and related canine breeds. Vet Sci 9:433, 2022. Pubmed reference: 36006348. DOI: 10.3390/vetsci9080433.
Zhang, X., Distl, O. :
A study of Rhodesian Ridgeback dogs indicates that the duplication responsible for hair ridge is not identical with the hypothesized locus for dermoid sinus. Anim Genet 53:231-233, 2022. Pubmed reference: 35067986. DOI: 10.1111/age.13172.
2021 Blondel, M., Deprey, J., Moissonnier, P. :
Type IV dermoid sinus, intramedullary dermoid cyst and spina bifida in a Cane Corso. J Small Anim Pract 62:810-815, 2021. Pubmed reference: 33025601. DOI: 10.1111/jsap.13240.
2019 Kopke, M.A., Jack, M.W., Baltzer, W.I., Wightman, P.F., Gal, A. :
Dermoid sinus type VI associated with spina bifida and tethered cord syndrome in a French Bulldog. J Vet Diagn Invest 31:294-297, 2019. Pubmed reference: 30734666. DOI: 10.1177/1040638719827626.
2015 Waldo, J.T., Diaz, K.S. :
Development and validation of a diagnostic test for Ridge allele copy number in Rhodesian Ridgeback dogs. Canine Genet Epidemiol 2:2, 2015. Pubmed reference: 26401330. DOI: 10.1186/s40575-015-0013-x.
2014 Barrios, N., Gómez, M., Mieres, M., Vera, F., Alvial, G. :
Spinal dermoid sinus in a Dachshund with vertebral and thoracic limb malformations. BMC Vet Res 10:54, 2014. Pubmed reference: 24593884. DOI: 10.1186/1746-6148-10-54.
2009 Andersson, L. :
Genome-wide association analysis in domestic animals: a powerful approach for genetic dissection of trait loci. Genetica 136:341-9, 2009. Pubmed reference: 18704695. DOI: 10.1007/s10709-008-9312-4.
2008 Rahal, S., Mortari, AC., Yamashita, S., Filho, MM., Hatschbac, E., Sequeira, JL. :
Magnetic resonance imaging in the diagnosis of type 1 dermoid sinus in two Rhodesian Ridgeback dogs. Can Vet J 49:871-6, 2008. Pubmed reference: 10713979.
2007 Karlsson, E.K., Baranowska, I., Wade, C.M., Salmon Hillbertz, N.H., Zody, M.C., Anderson, N., Biagi, T.M., Patterson, N., Pielberg, G.R., Kulbokas, E.J., Comstock, K.E., Keller, E.T., Mesirov, J.P., von Euler, H., Kämpe, O., Hedhammar, A., Lander, E.S., Andersson, G., Andersson, L., Lindblad-Toh, K. :
Efficient mapping of mendelian traits in dogs through genome-wide association. Nat Genet 39:1321-8, 2007. Pubmed reference: 17906626. DOI: 10.1038/ng.2007.10.
Salmon Hillbertz, N.H., Isaksson, M., Karlsson, E.K., Hellmén, E., Pielberg, G.R., Savolainen, P., Wade, C.M., von Euler, H., Gustafson, U., Hedhammar, A., Nilsson, M., Lindblad-Toh, K., Andersson, L., Andersson, G. :
Duplication of FGF3, FGF4, FGF19 and ORAOV1 causes hair ridge and predisposition to dermoid sinus in Ridgeback dogs. Nat Genet 39:1318-20, 2007. Pubmed reference: 17906623. DOI: 10.1038/ng.2007.4.
2006 Hillbertz, NH., Andersson, G. :
Autosomal dominant mutation causing the dorsal ridge predisposes for dermoid sinus in Rhodesian ridgeback dogs. J Small Anim Pract 47:184-8, 2006. Pubmed reference: 16573760. DOI: 10.1111/j.1748-5827.2006.00016.x.
2005 Hillbertz, NH. :
Inheritance of dermoid sinus in the Rhodesian ridgeback. J Small Anim Pract 46:71-4, 2005. Pubmed reference: 15736812.
2000 Tshamala, M., Moens, Y. :
True dermoid cyst in a Rhodesian ridgeback Journal of Small Animal Practice 41:352-353, 2000. Pubmed reference: 11002937.
1999 Cornegliani, L., Ghibaudo, G. :
A dermoid sinus in a Siberian Husky Veterinary Dermatology 10:47-49, 1999.
1998 Booth, M.J. :
Atypical dermoid sinus in a chow chow dog Journal of the South African Veterinary Medical Association 69:102-104, 1998.
1995 Fatone, G., Brunetti, A., Lamagna, F., Potena, A. :
Dermoid sinus and spinal malformations in a Yorkshire terrier: Diagnosis and follow-up Journal of Small Animal Practice 36:178-180, 1995. Pubmed reference: 7603060.
1993 Marks, S.L., Harari, J., Dernell, W.S. :
Dermoid Sinus in a Rhodesian Ridgeback Journal of Small Animal Practice 34:356-358, 1993.
1992 Kása, F., Kása, G., Kussinger, S. :
[Dermoid sinus in a Rhodesian ridgeback. Case report]. Tierarztl Prax 20:628-31, 1992. Pubmed reference: 1481220.
1989 Williams, ML. :
The ridgeback anomaly. Arch Dermatol 125:1144, 1989. Pubmed reference: 2642687.
1986 Gammie, JS. :
Dermoid sinus removal in a Rhodesian ridgeback dog. Can Vet J 27:250-1, 1986. Pubmed reference: 17422670.
1979 Hathcock, JT., Clampett, EG., Broadstone, RV. :
Dermoid sinus in a Rhodesian Ridgeback. Vet Med Small Anim Clin 74:53-6, 1979. Pubmed reference: 256350.
1970 Antin, IP. :
Dermoid sinus in a Rhodesian Ridgeback dog. J Am Vet Med Assoc 157:961-2, 1970. Pubmed reference: 4919487.
1966 Mann, G.E., Stratton, J. :
Dermoid sinus in the Rhodesian Ridgeback Journal of Small Animal Practice 7:631-642, 1966. Pubmed reference: 5951011. DOI: 10.1111/j.1748-5827.1966.tb04388.x.
1957 Lord, L.H., Cawley, A.J., Gilray, J. :
Mid dorsal dermoid sinuses in Rhodesian Ridgeback dogs - a case report Journal of the American Veterinary Medical Association 131:515-518, 1957.

Edit History

  • Created by Frank Nicholas on 20 Nov 2010
  • Changed by Frank Nicholas on 26 Sep 2011
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  • Changed by Imke Tammen2 on 10 Jun 2024