Polydactyl Maine Coon

Maine Coons were known to often be polydactyl – having extra toes on two or all four feet. It is estimated that in the 50s and 60s, when the breed was first recognized, almost half of all MCO were polydactyl – possibly 40 %.

At WesterosCat Maine Coon we do not have polydactyl cats in breeding, but knowing a little about the background and genetics is good nevertheless.


Maine Coon har ofte vært polydaktyle – hatt ekstra tær på to eller alle fire poter. Det er estimert at i 50- og 60-årene, da rasen først ble registrert, så var nesten halvparten av alle Maine Coon polydaktyle – antagelig rundt 40 %.

WesterosCat Maine Coon har ikke polydaktyle i avl, men det å vite litt om bakgrunnen og genetikken er bra i alle fall.


There are basically two types of polydactyl paws:

  • “Mitten” – extra “thumb” toes
  • “Pattyfoot” – several extra toes, but no “thumb”

Det fins i hovedsak to typer polydaktyle poter:

  • “Votter” (mitten) – med ekstra tomler
  • “Pailabber” (pattyfoot) med flere ekstra tær uten tommel
polydactyly from Messybeast.com

from Messybeast.com

The Genetics – Genetikken

Polydactyly is normally a dominant trait, and can be inherited from one of the parents. In Maine Coon the most common mutation is called the “Hemingway mutation” Hw. This can be DNA-tested.

Polydaktyli er vanligvis et dominant anlegg, og kan nedarves fra én av foreldrene. Innen Maine Coon-rasen kalles den vanligste mutasjon “Hemingway-mutasjonen” HW. Den kan DNA-testes.

Type Mutation Can be tested where Found in breeds
“Mitten” Hw P forepaws LIMBR1 c.479A>G MyCatDNA, Genoscoper MCO, Pixiebob
PP all paws LIMBR1 c.481A>T MyCatDNA, Genoscoper Domestic shorthair
PP all paws LIMBR1 G257C MyCatDNA Domestic shorthair
“Pattyfoot” unknown MCO

From MyCatDNA:

Polydactyly means the presence of extra digits. Mutations in the ZRS modulator cause polydactyly in cats. Three different causative mutations have heen found from cat lines originating from different geographical locations. All of these mutations result in a mutation-typical phenotype.

The ZRS modulator is responsible for controlling the signaling molecule SHH in the developing limb buds. Mutations in this modulator cause polydactyly in cats via altered modulator function. Polydactyly in Hemingway cats is caused by a dominant mutation of the ZRS modulator (A479G). The same mutation has been found in other polydactylous cats in North America. This mutation causes polydactyly in the forelimbs. Two other dominant ZRS modulator mutations, (G257C) and CA481T), causing polydactyly have been found in British cats. These mutations cause polydactyly in all limbs. The final appearance of the cat will also depend on its genetic makeup at other loci.


The lab Antagéne in France is doing research on the genetics of polydactyl Maine Coons and it is possible to participate.

Laboratoriet Antagene i Frankrike har forskning på genetikken bak polydaktyl Maine Coon – og man kan bidra til forskningen.

Breeding polydactyls – polydaktyl avl

Today only some of the registries allow breeding with polydactyl Maine Coons. In FIFe, breeding polydactyl cats were forbidden from 1. January 2014, a motion passed at the General Assembly in 2013. In FIFe we can not breed or show polydactyl Maine Coons.

I dag er det kun noen få forbund som godtar avl på polydaktyle Maine Coon. I FIFe ble polydakyli forbudt fra 1. januar 2014, sak vedtatt på GA i 2013. I FIFe (NRR) kan vi ikke avle på eller stille ut polydaktyle Maine Coon.

Registry MCO recognized breed poly can be registered and bred poly can be shown
CFA 1976 yes never
TICA 1979 yes accepted in 2015
FIFe 1982 forbidden from 2013 never
WCF no no
GCCF no no
CFF yes  ?
NZCF yes yes

There are also other registries – if you have information about what rules they have I am happy to include that here, just contact me.

Read more:

Messy Beast – about the genetics and background

Alterskjær Maine Coon about breeding polydactyl Maine Coon – in Norwegian



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