The Manx Cat

and implications of a short tail mutation

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Description




  • Domestic felines are born with a naturally occurring genetic mutation that causes a shortening of the spine, resulting in the cats having a stub or being tail-less
  • The gene that causes this mutation is dominant and is called mutant gene M
  • Tail length and number of vertebrae varies with each cat as a result of the disease
  • The abnormalities in the spine can lead to neurological disease over time

History


  • One of the oldest known breeds of domestic cat
  • Descended from African Wildcat (F.Silvestris lybica)
  • Breed originated in the Isle of Man, within the British Isles, where the mutation arose
  • Became prominent due to limited genetic diversity
  • The International Cat Association describes the Manx as a “bowling ball” shaped cat

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Symptoms


  • The cat is born with little or no tail
  • Abnormally long hind legs
  • Broad/solid stature
  • Often it's appearance and gait is compared to that of a rabbit
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Health Problems


  • Spina bifida can occur as a spinal defect “Manx Syndrome”
  • Other issues with the vertebrae, such as fused, missing, deformed, and poorly developed spinal bones
  • Bowel/bladder problems from spina bifida (constipation and fetal incontinence from shape of spine)
  • Possible paralysis from shape of

    Vertebrae

  • Meningeal dysplasia (abnormal formation of the meninges, a.k.a the tissue wrapping the spinal cord)

  • Spinal cord dysplasia (malformation of the spinal cord)

  • Neurological and motor issues

Manx kitten with a neurological disorder

Dog Befriends Disabled Kitten
Introducing.... The Cabbits!
Manx Syndrome - Winnie

Heredity

● Manx results from breeding a manx cat with another manx, transmitted by autosomal dominant gene M

● If cats are MM gene homozygous in utero, this is lethal and results in miscarriage

● Tailless cats can only carry one copy of the gene, otherwise it’s fatal

● Gene M is considered a lethal gene by most researchers

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Genotypes and Phenotypes

●Cats must be Heterozygous for dominant allele for the trait to occur

●95% of manx cats with short-tail phenotypes were heterozygous for M-mutations, meaning they have a copy of the M gene

●Tailed individuals produced by Manx cats are mm homozygous and not considered Manx cats

●These mutant alleles appeared to be largely lineage specific

Prevention and Treatment

●More than 12 different show associations recognize the Manx breed and have their own standards to breed towards

●There are no current methods of preventing mutant gene M from appearing in felines as it is linked to the phenotype that characterizes the Manx Cat Syndrome

●When breeding a cat who carries the gene, there is always a chance they will pass the disease to their offspring, as 95% of all Manx cats are heterozygous

●Some Manx have better health than others, so those intent on breeding them should focus on breeding the healthiest offspring for the best fate of the breed.

●In the future, if we were able to figure out how environmental factors and the gene’s expression worked, then it may be possible to prevent the disease

Opinion

In my opinion efforts at preventing and attempting to eradicate the manx cat syndrome don't seem to be a big priority for breeders because essentially the best way to do that would be to stop trying to produce more of this breed which wouldn't be beneficial to them. It is a widely accepted breed by show associations and has been around a long time despite all of the genetic issues. I believe that one of the main reasons for this is that people see the manx cat as being cute and unique and that they possibly don't fully understand or aren't educated on the implications of the short tail mutation. Educating more people on the health issues and consequences would be a good step towards reducing the amount of cats with manx syndrome and then working towards breeding out the short tail so that the genetic disorder doesn't continue to be prevalent in future generations.


Discussion point: Do you think that with all the health issues associated with this breed that breeders should continue breeding for them? If yes explain why and If not then what are some methods towards prevention you might suggest.

References

●Deforest, M. E., and P.K.Basrur. “Malfunctions and the Manx Cat Syndrome in Cats.” The Canadian Veterinary Journal (1979):304-14.

●Eddie’s Wheels, 2014, Yes Disabled Cats Use Wheelchairs, http://eddieswheels.com/yes-disabled-cats-do-use-wheelchairs/ (October 14th, 2014)

●Havlicek, Martin, et al. “Surgical Management of Vertebral Malformation in a Manz Cat.” Journal of Feline Medicine and Surgery 11.6 (2009): 514:7.

●Manx Cat Health, 2014, The Manx Cat, http://cats.lovetoknow.com/Manx_Cat_Health. (October 15th, 2014)

●Meggitt, Jane, 2014. Manx Cat Problems with Incontinence, The Nest Journal. http://pets.thenest.com/manx-cat-problems-incontinence-9517.html (October 14th

●Sexton, Paul. Manx Cat. 121 Vol. The Nielson Company, 2009.

●“Short Tailed Cat Has A Very Big Problem.” Northwest Florida Daily News: D.3. 2014.

●Universities Federation For Animal Welfare, 2011, UFAW, http://www.ufaw.org.uk/manxsyndrome.php#Genetics. (October 14th, 2014)

http://www.tica.org/cat-breeds/item/233