OMIA:000810-9685 : Polydactyly in Felis catus (domestic cat)

In other species: rock pigeon , chicken , turkey , dog , horse , pig , Arabian camel , guanaco , llama , Western roe deer , taurine cattle , goat , sheep , domestic guinea pig , alpaca , springbok

Categories: Limbs / fins / digit / tail phene

Links to possible relevant human trait(s) and/or gene(s) in OMIM: 174500 (trait) , 605522 (gene) , 188740 (trait)

Mendelian trait/disorder: yes

Mode of inheritance: Autosomal dominant

Considered a defect: yes

Key variant known: yes

Year key variant first reported: 2008

Cross-species summary: Often called preaxial polydactyly (PPD)

Species-specific symbol: Pd

History: This trait occurs at a very high frequency in the population of cats that has long existed in the grounds of Ernest Hemingway's house in Key West, Florida ( These "Hemingway" cats descend from a cat given to Hemingway by a ship's captain in the 1930s (Gwin, 2007).

Inheritance: Hamelin et al. (2020): "Polydactyly in Maine Coon cats is inherited as an autosomal dominant trait with incomplete penetrance and variable expressivity, and this trait is characterised by genetic heterogeneity in the Maine Coon breed."

Molecular basis: Polydactyly results from faults in the regulation of the developmental gene Sonic Hedgehog (SHH), which is expressed only at the border of the posterior limb bud, in a region called the zone of polarizing activity (ZPA). The faults in regulation result from mutations in an enhancer located in the LMBR1 gene, located about 1 MB upstream of SHH. The enhancer is called the ZPA regulatory sequence (ZRS). Thus polydactyly results from mutations in ZRS, which affect expression of SHH in the developing limb bud. Lettice et al. (2008) showed that polydactyly in cats is due to point mutations in the control region ZRS, whose product regulates the transcription and translation of the signalling molecule sonic hedgehog (SHH). All of the Hemingway polydactylous cats examined had the same point mutation; British polydactylous cats had two different point mutations in the same gene. Mutations in ZRS in humans and mice also give rise to polydactyly.

Clinical features: Polydactyly in cats is a congenital deformity, clinically characterized by the presence of more than 18 digits in total at birth, with the additional digit(s) on either their front and/or hind limb(s). A variety of combinations of different numbers of extra toes per paw have been observed, while the distribution of extra digits exhibits a non-continuous statistical pattern (Lange et al., 2013). Polydactyl cats not only have an unusual number and shape of digits, but they may also exhibit unharmful altered conformation of carpus and tarsus (Hamelin et al., 2016). IT thanks DVM student Ophelia Xinran Pan, who provided the basis of this contribution in May 2023.

Breeds: Domestic Shorthair, Maine Coon (Cat) (VBO_0100154), Pixiebob (Cat) (VBO_0100191).
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
SHH sonic hedgehog Felis catus - no genomic information (-..-) SHH Homologene, Ensembl , NCBI gene
LMBR1 limb development membrane protein 1 Felis catus A2 NC_058369.1 (167593572..167440874) LMBR1 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
434 Polydactyly LMBR1 Pd^UK2 regulatory Naturally occurring variant Felis_catus_9.0 A2 g.169532842T>A regulatory variant in the ZPA regulatory sequence (ZRS); published as AGACACAG[A/T]AATGAG 2008 18156157 Genomic position in Felis_catus_9.0 provided by Joshua Khamis.
432 Maine Coon (Cat) Polydactyly LMBR1 Pd^Hw regulatory Naturally occurring variant Felis_catus_9.0 A2 g.169532844T>C regulatory variant in the ZPA regulatory sequence (ZRS); published as AGACAC[A/G]GAAATGAG 2008 18156157 Genomic position in Felis_catus_9.0 provided by Joshua Khamis, Leslie Lyons and Reuben Buckley.
433 Polydactyly LMBR1 Pd^UK1 regulatory Naturally occurring variant Felis_catus_9.0 A2 g.169533066C>G regulatory variant in the ZPA regulatory sequence (ZRS); published as CC[G/C]GTG 2008 18156157 Genomic position in Felis_catus_9.0 provided by Joshua Khamis, Leslie Lyons and Reuben Buckley.

Cite this entry

Nicholas, F. W., Tammen, I., & Sydney Informatics Hub. (2023). OMIA:000810-9685: 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.

2020 Hamelin, A., Conchou, F., Fusellier, M., Duchenij, B., Vieira, I., Filhol, E., Dufaure de Citres, C., Tiret, L., Gache, V., Abitbol, M. :
Genetic heterogeneity of polydactyly in Maine Coon cats. J Feline Med Surg 22:1103-1113, 2020. Pubmed reference: 32067556. DOI: 10.1177/1098612X20905061.
2017 Hamelin, A., Begon, D., Conchou, F., Fusellier, M., Abitbol, M. :
Clinical characterisation of polydactyly in Maine Coon cats. J Feline Med Surg 19:382-393, 2017. Pubmed reference: 26862149. DOI: 10.1177/1098612X16628920.
2014 Lange, A., Nemeschkal, H.L., Müller, G.B. :
Biased polyphenism in polydactylous cats carrying a single point mutation: The Hemingway model for digit novelty. Evol. Biol. 41:262–275, 2014. DOI: 10.1007/s11692-013-9267-y.
2009 Lockwood, A., Montgomery, R., McEwen, V. :
Bilateral radial hemimelia, polydactyly and cardiomegaly in two cats. Vet Comp Orthop Traumatol 22:511-3, 2009. Pubmed reference: 19876522. DOI: 10.3415/VCOT-08-12-0124.
2008 Lettice, LA., Hill, AE., Devenney, PS., Hill, RE. :
Point mutations in a distant sonic hedgehog cis-regulator generate a variable regulatory output responsible for preaxial polydactyly. Hum Mol Genet 17:978-85, 2008. Pubmed reference: 18156157. DOI: 10.1093/hmg/ddm370.
2007 Gwin, P. :
Hemingway's cats: to have or have not? National Geographic 211:30, 2007.
1995 Wenthe, M., Lazarz, B. :
A case of atavistic polydactyly at the hind limb of a cat [German] Kleintierpraxis 40:617-619, 1995.
1992 Wittmann, F. :
Polydactylism in a cat. Praktische Tierarzt 73:709, 1992.
1976 Todd, NB., Todd, LM. :
Mutant allele frequencies among domestic cats in some eastern areas of Canada: regional homogeneity of factors in Canadian Atlantic Provinces and the French colony of Saint Pierre. J Hered 67:368-72, 1976. Pubmed reference: 1021595.
1968 Sis, RF., Getty, R. :
Polydactylism in cats. Vet Med Small Anim Clin 63:948-51, 1968. Pubmed reference: 5188319.
1966 Todd, NB. :
The independent assortment of dominant white and polydactyly in the cat. J Hered 57:17-18, 1966. Pubmed reference: 5917255.
1964 Todd, N.B., Jones, T.C. :
On independent assortmant of dominant white and polydactyly in the cat Journal of Cat Genetics 1:16-17, 1964.
1961 Chapman, V.A., Zeiner, F.N. :
The anatomy of polydactylism in cats with observations on genetic control Anatomical Record 141:205-217, 1961. Pubmed reference: 13878202.
1947 Danforth, CH. :
Morphology of the feet in polydactyl cats. Am J Anat 80:143-71, 1947. Pubmed reference: 20286212.
Danforth, CH. :
Heredity of polydactyly in the cat. J Hered 38:107-12, 1947. Pubmed reference: 20242531.
1909 Bateson, W. :
Mendel’s Principles of Heredity. Cambridge University Press, London , 1909. URL:
1904 Davenport, C.B. :
Wonder horses and Mendelism. Science 19:151-3, 1904. Pubmed reference: 17839722. DOI: 10.1126/science.19.473.151.
1902 Torrey, HB. :
Prepotency in polydactylous cats Science 16:554-5, 1902. Pubmed reference: 17833849. DOI: 10.1126/science.16.405.554.
1873 Tait, L. :
Note on a polydactylous cat from Cookham-Dean. Nature 7:323 only, 1873. DOI: 10.1038/007323b0.

Edit History

  • Created by Frank Nicholas on 19 Nov 2010
  • Changed by Frank Nicholas on 29 Sep 2011
  • Changed by Frank Nicholas on 30 Sep 2011
  • Changed by Frank Nicholas on 09 Dec 2011
  • Changed by Frank Nicholas on 02 May 2012
  • Changed by Imke Tammen2 on 31 Aug 2021
  • Changed by Imke Tammen2 on 26 Feb 2022
  • Changed by Imke Tammen2 on 07 Jun 2023
  • Changed by Imke Tammen2 on 10 Nov 2023