View source for Scottish Fold

{{Short description|Cat breed having specific gene mutation}}
{{Redirect|Highland Straight|the long-haired variant of the British Shorthair|British Longhair|other uses of "Highland" with regard to cats|Highland cat (disambiguation)}}
{{Use dmy dates|date=January 2024}}
{{Infobox Catbreed
| name          = Scottish Fold
| image         = Blue Scottish Fold Cat.png
| imagecaption  = Lilac coloured adult Scottish Fold, displaying round face, round eyes and forward-folded ears
| altname       = Scot Fold
| country       = {{flag|Scotland}}
| cfastd        = https://cfa.org/wp-content/uploads/2024/03/scottish-fold-standard.pdf
| acfastd       = http://acfacat.com/Breed%20Standards/SCOTTISH%20FOLD%20SHORTHAIR.pdf
| ticastd       = https://tica.org/wp-content/uploads/2024/08/scottish_breed_group_-_4_columns-landscape.pdf
| wcfstd        = https://wcf.de/pdf-en/breed/SFS_en_2023-08-13.pdf
| ccastd        =
| acfstd        =
| gccfstd       =
| fifestd       =
| otherstd      =
| note          = Not recognised by [[Fédération Internationale Féline|FIFe]] and [[Governing Council of the Cat Fancy|GCCF]]
}}

The '''Scottish Fold''' is a distinctive [[List of cat breeds|breed]] of [[Cat|domestic cat]] characterised by a natural [[Dominance (genetics)|dominant gene]] [[mutation]] associated with [[osteochondrodysplasia]]. This genetic anomaly affects [[cartilage]] throughout the body, causing the [[Cat anatomy|ears]] to "fold", bending forward and down towards the front of the head. While this trait contributes to the breed's unique appearance, often described as "[[owl]]-like",<ref name=CFA>{{cite web|title=Scottish Fold - CFA|work=The Cat Fanciers' Association |url=https://cfa.org/breed/scottish-fold/|archive-url= https://archive.today/20241125151158/https://cfa.org/breed/scottish-fold/|url-status=live|archive-date=25 November 2024|access-date=26 November 2024|publisher=Cat Fanciers' Association}}</ref> it also causes health problems.

The breed's name, originally '''Lop-ears''' or '''Lops''' after the [[Lop rabbit|lop-eared rabbit]], became ''Scottish Fold'' in 1966.{{r|CFA}} Depending on registries, longhaired Scottish Folds are varyingly known as '''Highland Fold''', '''Scottish Fold Longhair''', '''Longhair Fold''', and '''Coupari'''.

Research has revealed that all Scottish Fold cats are affected by [[osteochondrodysplasia]], a [[Birth defect|developmental abnormality]] that affects [[cartilage]] and [[bone]] development throughout the body. This condition causes the ear fold as well as malformed bone structures, and the breed can develop severe painful degenerative joint diseases at an early age.<ref name="ufaw">{{cite web |url= http://www.ufaw.org.uk/OSTEOCHONDRODYSPLASIASCOTTISHFOLD.php |title=Genetic welfare problems of companion animals: Scottish Fold: Osteochondrodysplasia |date=2011 |publisher=Universities Federation for Animal Welfare |access-date=2 February 2012 |archive-url= https://web.archive.org/web/20120319161612/http://www.ufaw.org.uk/OSTEOCHONDRODYSPLASIASCOTTISHFOLD.php |archive-date=19 March 2012}}</ref> Because of these health conditions, breeding Fold cats is prohibited in several countries, and some major cat registries do not recognise the breed.

==History==
===Origin===
The original Scottish Fold was a white barn cat named Susie, who was found at a farm near [[Coupar Angus]] in [[Tayside]], [[Scotland]], in 1961. Susie's ears had an unusual fold in their middle, making her resemble an [[owl]]. When Susie had kittens, two of them were born with folded ears, and one was acquired by William Ross and his wife, Molly, neighbouring farmers who were cat fanciers.<ref name="CFApdf">{{cite web |title=Scottish Fold Brochure |url=https://cfa.org/wp-content/uploads/2023/09/scottish-fold-brochure.pdf |website=Cat Fanciers' Association |access-date=22 January 2024 |archive-date=28 May 2024 |archive-url=https://web.archive.org/web/20240528064324/https://cfa.org/wp-content/uploads/2023/09/scottish-fold-brochure.pdf }}</ref>  The [[breeding program]]me produced 76 kittens in the first three years – 42 with folded ears and 34 with straight ears. The conclusion from this was that the ear mutation is due to a simple dominant gene.<ref name="Fanciers">{{cite web |url= http://fanciers.com/breed-faqs/scottish-fold-faq.html |title=Scottish Fold FAQ |publisher=Fanciers.com |access-date=3 October 2009}}</ref> Ross registered the breed with the [[Governing Council of the Cat Fancy]] (GCCF) in the [[United Kingdom]] in 1966 and started to breed Scottish Fold kittens with the help of [[geneticist]] Pat Turner. However by the early 1970s the GCCF stopped registering the cat due to concerns about potential health issues such as ear infections and deafness.
In 1970 the first Scottish Fold kittens were introduced to America via a Neil Todd of [[Massachusetts]] who was researching the mutation. Further cats were brought over and the Scottish Fold breeding program continued with [[American Shorthair]]s and [[British Shorthair]]s being introduced.<ref name="Pegken">{{cite web |title=Scottish Fold history |url=https://www.pegkenscats.com/page/page/3536013.htm |website=Pegkens Scottish Folds |access-date=22 January 2024}}</ref>

=== Breed recognition ===
In 1978 the [[Cat Fanciers' Association]] (CFA) granted the breed championship status.
In the mid 1980s the long-haired version started to gain recognition.<ref name="Pegken"/>
The International Cat Association (TICA) was the first registry to recognized the longhairs for championship competition in the 1987–88 show season and CFA followed in 1993–94.

==Characteristics==
[[File:Rumfold Red Bull.png|right|thumb|Scottish Fold longhair kitten]]

===Ears===
[[File:Straight-eared Scottish Fold.jpg|thumb|Scottish Fold with straight ears (Scottish Straight)]]

Scottish Fold kittens that do not develop folded ears are known as Scottish Straights.<ref>{{cite web |title=Scottish Straight Breed |url=https://www.tica.org/scottish-straight-breeders?view=article&id=873:scottish-straight-breed&catid=79 |website=The International Cat Association |access-date=26 May 2024}}</ref>

{{Blockquote|The breed's distinctive folded ears are produced by an incomplete dominant gene that affects the cartilage of the ears, causing the ears to fold forward and downward, giving a cap-like appearance to the head. Smaller, tightly folded ears set in a cap-like fashion are preferred to a loose fold and larger ear. The large, round eyes and rounded head, cheeks, and whisker pads add to the overall rounded appearance. Despite the folded ears, folds still use their aural appendages to express themselves—the ears swivel to listen, lie back in anger and prick up when the treat bag rustles.<ref name="Pegken" />}}

===Body===
The Scottish Fold is a medium to large sized cat, which can come in any colour, even calico. Males typically weigh {{cvt|4–6|kg|lb}}, and females weigh {{cvt|2.7–4|kg|lb}}. The Fold's entire body structure, especially the head and face, is generally rounded, and the eyes large and round. The nose is short with a gentle curve, and the cat's body is well-rounded with a padded look and medium-to-short legs. The head is domed at the top, and the neck very short. The broadly-spaced eyes give the Scottish Fold a "sweet expression".<ref name="Fanciers" />

===Coat===
[[File:Scottish fold cat named Oreo.jpg|thumb|right|200px|A Scottish fold kitten]]
Scottish Folds can be either long- or short-haired, and they may have nearly any coat colour or combination of colours (including white).<ref name="Fanciers" /> Shorthair Scottish Folds have thick and soft fur, with longhair Folds having longer fur and tufts located around the extremities.<ref name="Fold Cat Breed Information 2017">"Scottish Fold Cat Breed Information, Pictures, Characteristics & Facts." CatTime, https://cattime.com/cat-breeds/scottish-fold-cats#/slide/1. Accessed 26 September 2017.</ref>

==Genetics==
An early study suggested that the fold is inherited as an autosomal dominant trait.<ref name="AustraliaVetJournal" /> A later study suggested an [[Autosomal dominant#Incomplete dominance|incomplete dominance]].<ref>{{cite journal |date=April 2008 |title=Incomplete dominant osteochondrodysplasia in heterozygous Scottish Fold cats |journal=The Journal of Small Animal Practice |volume=49 |number=4 |pages=197–9 |doi=10.1111/j.1748-5827.2008.00561.x |last1=Takanosu |first1=M. |last2=Takanosu |first2=T. |last3=Suzuki |first3=H. |last4=Suzuki |first4=K. |pmid=18339089}}</ref> A cat with folded ears may have either one ([[Zygosity|heterozygous]]) or two copies (homozygous) of the dominant fold gene (Fd). A cat with normal ears should have two copies of the normal gene (fd).

{| class="wikitable" style="text-align: center; "
|-
| colspan="2" rowspan="2" |
! colspan="2" | Homozygous fold
|-
! Fd || Fd
|-
! rowspan="2" | Homozygous fold
! Fd
| Fd Fd || Fd Fd
|-
! Fd
| Fd Fd || Fd Fd
|}

{| class="wikitable" style="text-align: center; "
|-
| colspan="2" rowspan="2" |
! colspan="2" | Heterozygous fold
|-
! Fd || fd
|-
! rowspan="2" | Homozygous fold
! Fd
| Fd Fd || Fd fd
|-
! Fd
| Fd Fd || fd Fd
|}

{| class="wikitable" style="text-align: center; "
|-
| colspan="2" rowspan="2" |
! colspan="2" | Straight-eared
|-
! fd || fd
|-
! rowspan="2" | Homozygous fold
! Fd
| Fd fd || Fd fd
|-
! Fd
| Fd fd || Fd fd
|}

Mating a homozygous fold with any cat will produce all folds, but because homozygous folds are prone to severe health issues, breeding for them is generally considered unethical. A homozygous to normal mating will produce only heterozygous folds but presumably in ethical breeding programs, there will be no homozygous cats available to breed from.

{| class="wikitable" style="text-align: center; "
|-
| colspan="2" rowspan="2" |
! colspan="2" | Straight-eared
|-
! fd || fd
|-
! rowspan="2" | Heterozygous fold
! Fd
| Fd fd || Fd fd
|-
! fd
| fd fd || fd fd
|}
The only generally accepted breeding gives a 50% chance of producing heterozygous folds and 50% chance of producing progeny with normal genes.

{| class="wikitable" style="text-align: center; "
|-
| colspan="2" rowspan="2" |
! colspan="2" | Heterozygous fold
|-
! Fd || fd
|-
! rowspan="2" | Heterozygous fold
! Fd
| Fd Fd || Fd fd
|-
! fd
| fd Fd || fd fd
|}

There is suspicion that some non-fold litters are genetically heterozygous folds but because of very low expression of the gene, appear to be straight-eared. Such kittens may develop folded ears initially which then straighten back out. Because of this there are suggestions by some breeders to avoid mating Folds with straight-eared Scottish Folds but only use British Shorthairs (BSH) as [[Outcrossing|outcross]].<ref name="nzcfecmeeting" /><ref>{{cite web |last=Sutton |first=Grace |title=Breed Article: Scottish Folds |url=http://cfa.org/Breeds/BreedsSthruT/ScottishFold/SFArticle.aspx |website=cfa.org |publisher=[[Cat Fanciers' Association]] |access-date=7 December 2013 |archive-date=2 December 2013 |archive-url=https://web.archive.org/web/20131202233621/http://www.cfa.org/Breeds/BreedsSthruT/ScottishFold/SFArticle.aspx }}</ref> If Scottish Shorthairs are to be used, they should be test mated to a BSH to make sure that they are not genetically folds.<ref name="nzcfecmeeting" /> If such apparent straight-eared cats are mated with a fold, there is a 75% chance of folds (25% homozygous folds, 50% heterozygous folds) and 25% chance of straight ears.

In 2016, the [[Mutation|genetic mutation]] responsible for the folded ears and the [[osteochondrodysplasia]] was identified. It was found in a gene encoding a calcium permeable ion channel, transient receptor potential cation channel, subfamily V, member 4 (''Trpv4'').<ref>{{Cite journal |pmid=27063440 |date=2016 |last1=Gandolfi |first1=B. |last2=Alamri |first2=S. |last3=Darby |first3=W.G. |last4=Adhikari |first4=B. |last5=Lattimer |first5=J.C. |last6=Malik |first6=R. |last7=Wade |first7=C.M. |last8=Lyons |first8=L.A. |last9=Cheng |first9=J. |last10=Bateman |first10=J.F. |last11=McIntyre |first11=P. |last12=Lamandé |first12=S.R. |last13=Haase |first13=B. |title=A dominant TRPV4 variant underlies osteochondrodysplasia in Scottish fold cats |journal=[[Osteoarthritis and Cartilage]] |volume=24 |issue=8 |pages=1441–50 |doi=10.1016/j.joca.2016.03.019 |doi-access=free}}</ref> The mutation is a V342F substitution (c.1024G>T) in the fifth ankyrin repeat within the N-terminal cytoplasmic domain. It was also found in a human patient with [[Kniest dysplasia|metatropic dysplasia]].<ref>{{Cite journal |pmid=20577006 |date=2010 |last1=Dai |first1=J. |last2=Kim |first2=O.H. |last3=Cho |first3=T.J. |last4=Schmidt-Rimpler |first4=M. |last5=Tonoki |first5=H. |last6=Takikawa |first6=K. |last7=Haga |first7=N. |last8=Miyoshi |first8=K. |last9=Kitoh |first9=H. |last10=Yoo |first10=W.J. |last11=Choi |first11=I.H. |last12=Song |first12=H.R. |last13=Jin |first13=D.K. |last14=Kim |first14=H.T. |last15=Kamasaki |first15=H. |last16=Bianchi |first16=P. |last17=Grigelioniene |first17=G. |last18=Nampoothiri |first18=S. |last19=Minagawa |first19=M. |last20=Miyagawa |first20=S.I. |last21=Fukao |first21=T. |last22=Marcelis |first22=C. |last23=Jansweijer |first23=M.C. |last24=Hennekam |first24=R.C. |last25=Bedeschi |first25=F. |last26=Mustonen |first26=A. |last27=Jiang |first27=Q. |last28=Ohashi |first28=H. |last29=Furuichi |first29=T. |last30=Unger |first30=S. |title=Novel and recurrent TRPV4 mutations and their association with distinct phenotypes within the TRPV4 dysplasia family |journal=[[Journal of Medical Genetics]] |volume=47 |issue=10 |pages=704–9 |doi=10.1136/jmg.2009.075358 |s2cid=925054 |url= https://pure.uva.nl/ws/files/1257940/93555_339667.pdf}}</ref>

==Acceptance==
Legal bans on the breeding and sometimes sale of Folds have been enacted in several countries, including Australia, Austria, Belgium, Netherlands, Norway, and Scotland, due to the breed's health issues, especially deformities and pain caused by [[osteochondrodysplasia]], which results in abnormalities in bone and cartilage throughout the body. Some of the major [[Cat registry|cat registries]], such as the [[Governing Council of the Cat Fancy|GCCF]] and [[Fédération Internationale Féline|FIFe]], do not recognise, nor allow for the registry and competition showing of, Scottish folds.

=== Legal bans ===
Due to the prevalence of [[osteochondrodysplasia]] in the breed {{see below|[[#Osteochondrodysplasia|below]]}}, several countries and states have prohibited breeding with Scottish folds, in order to protect animal welfare. Banning countries include the [[Netherlands]] in 2014,<ref name=":0">{{Cite web |publisher=Netherlands Food and Consumer Product Safety Authority |date=31 October 2022 |title=Fokken met katten - Honden en katten |url= https://www.nvwa.nl/onderwerpen/honden-en-katten/fokken-met-uw-hond-of-kat/fokken-met-katten |access-date=1 April 2023 |website=NVWA.nl |language=nl}}</ref> [[Austria]] in 2020,<ref>{{Cite web |publisher=Tierschutzombudsstelle Wien |title=Qualzucht bei Katzen |url= https://www.tieranwalt.at/de/Projekte/Qualzucht_ALT/Qualzucht-bei-Katzen/iActivityId__433.htm |access-date=1 April 2023 |website=Tieranwalt.at |language=de}}</ref><ref>{{Cite web |title=RIS - Tierschutzgesetz - Bundesrecht konsolidiert, Fassung vom 01.04.2023 |url= https://www.ris.bka.gv.at/GeltendeFassung.wxe?Abfrage=Bundesnormen&Gesetzesnummer=20003541 |access-date=1 April 2023 |website=RIS.BKA.gv.at}}</ref> [[Flanders]] ([[Belgium]]) in 2021,<ref name=":1">{{Cite web |title=Verbod op de kweek en het verhandelen van fold katten |url= https://www.vlaanderen.be/verbod-op-de-kweek-en-het-verhandelen-van-fold-katten |access-date=1 April 2023 |website=Vlaanderen.be |language=nl}}</ref> [[Victoria (state)|Victoria]] ([[Australia]]).<ref>{{Cite web |publisher=Victoria Department of Jobs, Precincts and Regions |date=6 July 2020 |title=Code of Practice for the Breeding of Animals with Heritable Defects that Cause Disease |url= https://agriculture.vic.gov.au/livestock-and-animals/animal-welfare-victoria/domestic-animals-act/codes-of-practice/code-of-practice-for-the-breeding-of-animals-with-heritable-defects-that-cause-disease |access-date=1 April 2023 |website=Agriculture Victoria}}</ref> The breed is also indirectly banned by Norwegian and Swedish legislation prohibiting the breeding of animals with genetic make up that makes it likely to produce unhealthy offspring.<ref>{{Cite web |last=Løkkevik |first=Ole |date=4 July 2023 |title=Mattilsynet: Avl på katterasen Scottish Fold er i strid med dyrevelferdsloven |url= https://direkte.vg.no/nyhetsdognet/news/mattilsynet-avl-paa-katterasen-scottish-fold-er-i-strid-med-dyrevelferdsloven.hEHPsLIky |access-date=4 July 2023 |website=VG |language=no}}</ref><ref>{{cite web |title=xtreme breeding in Europe - Mapping of legislation |url=https://www.eurogroupforanimals.org/files/eurogroupforanimals/2023-11/2023_11_30_Extreme%20breeding%20in%20Europe%20-%20Mapping%20of%20legislation%20FINAL.pdf |website=[[Eurogroup for Animals]] |access-date=22 January 2024}}</ref>  Some countries have also banned selling<ref name=":1" /> of Scottish fold cats, or the breeding with any cat that bears the gene mutation resulting in osteochondrodysplasia, so even breeding with some of the Scottish straights may be legally restricted.<ref name=":0" /> Potential parent cats can be tested for this mutation before breeding.<ref>{{Cite web |title=Scottish Fold |publisher=Veterinary Genetics Laboratory, [[University of California, Davis]] |url= https://vgl.ucdavis.edu/test/scottish-fold |access-date=1 April 2023 |website=vgl.ucdavis.edu}}</ref>

=== Registry bans ===
Because of its health problems, the breed is not accepted by either the [[Governing Council of the Cat Fancy]]<ref>{{Cite web|title=Cat Breeds not recognised by GCCF but with some recognition by WCC members|date=2024|work=GCCFCats.org|publisher=[[Governing Council of the Cat Fancy]]|url=https://www.gccfcats.org/wp-content/uploads/2024/11/Unrecognised-Breeds-11.2024.pdf|access-date=15 May 2025}}</ref><ref name="GCCF-health">{{cite web|title=The GCCF says Health and Welfare Come First|work=GCCFCats.org|publisher=[[Governing Council of the Cat Fancy]]|url=https://www.gccfcats.org/welfare/|archive-url= https://web.archive.org/web/20240225171747/https://www.gccfcats.org/Welfare/|archive-date=25 February 2024|url-status=live|access-date=15 May 2025}}</ref> or the [[Fédération Internationale Féline]] (FIFe).<ref>{{Cite web|title=Breeds|website=FIFeWeb.org|publisher=[[Fédération Internationale Féline]]|url=https://fifeweb.org/cats/breeds/|archive-date=22 April 2025|archive-url=https://web.archive.org/web/20250422142526/https://fifeweb.org/cats/breeds/|url-status=live|access-date=15 May 2025}}</ref><ref name="FIF-breeding">{{cite web|title=Health & Welfare Rules|at=§3.5.2 "Genetic Diseases"|work=FIFeWeb.org|publisher=[[Fédération Internationale Féline]]|url=https://fifeweb.org/health-welfare-rules/#3.5|archive-url=https://web.archive.org/web/20250319083945/https://fifeweb.org/health-welfare-rules/#3.5|archive-date=19 March 2025|url-status=live|access-date=15 May 2025}}</ref>  GCCF withdrew registrations in 1971 due to crippling deformity of the limbs and tail in some cats and concerns about genetic difficulties and ear problems such as [[infection]], [[mites]], and [[deafness]], but the Folds were exported to the [[Americas]] and the breed continued to be established, using [[outcross]]ing with [[British Shorthair]]s and [[American Shorthair]]s. Since the initial concerns were brought, the Fold breed has not had the mite and infection problems.{{r|CFA}}

[[Cat Fanciers' Association]] breeders have stated that using only fold to non-fold breeding has eliminated problems with stiff tails, shortened tails, and bone [[lesions]].{{r|CFA}} In the FIFe discussion, the representative for British breeders claimed that they were not seeing the problem in their cats, and that the study which showed that all heterozygous also have the condition had a small sample size. An offer of free [[Radiography|X-ray radiography]] was presented to 300 breeders to find a Fold cat with healthy hind legs, but it was never taken up.<ref>{{cite web |url= http://www.kolumbus.fi/minna.peltonen/fifenpts.htm |title= FIFe decision not to accept Scottish Fold breed in May 2003 |access-date= 2 February 2012 |archive-date= 10 March 2013 |archive-url= https://web.archive.org/web/20130310094918/http://www.kolumbus.fi/minna.peltonen/fifenpts.htm }}</ref><ref>{{cite web |url= http://au.dir.groups.yahoo.com/group/ScottishFoldandScottishShorthairGroup/message/199?o=1&d=-1 |archive-url= https://archive.today/20120701174601/http://au.dir.groups.yahoo.com/group/ScottishFoldandScottishShorthairGroup/message/199?o=1&d=-1 |archive-date=1 July 2012 |title=Email from ScottishFoldandScottishShorthairGroup |date=2008 |access-date=2 February 2012}}</ref> A similar offer was set up by the [[World Cat Federation]] together with researcher [[Leslie A. Lyons|Leslie Lyons]] but there was also no response. FIFe stated that they will not consider recognizing Scottish Folds if breeders will not allow their breed to be scrutinized.<ref>{{cite web |url= http://www.worldcatcongress.org/wp/lib.html |title=Minutes of the Business Meeting of the World Cat Congress: Arnhem, the Netherlands: 14th April. 2009 |access-date=2 February 2012}}</ref>

In a report on Scottish Folds, the Breed Standards Advisory Council for [[New Zealand Cat Fancy]] (NZCF) states that "Breeders may not have appreciated the strength of the evidence that heterozygous cats can and do develop [feline] OCD." While research shows that all heterozygous Folds develop OCD, and anecdotal evidence shows that heterozygous Folds can and do develop OCD, they do not show whether mildly affected parents are more likely to have mildly affected offspring. They also do not show what percentage of Folds are severely affected. The report states that there is not enough information to justify banning Scottish Fold matings, but enough to justify a level of concern.<ref name="nzcfecmeeting">{{cite web |url= http://www.nzcf.com/downloads/EC%20Meeting%20Sept%202011.doc |title=Minutes of Executive Council Meeting No: 28 (doc) |date=24–25 September 2011 |publisher=New Zealand Cat Fancy |access-date=3 February 2012}}</ref> Recommended guidelines include:

* A requirement for periodic vet examination of breeding cats for any evidence of lameness, stiffness, or pain—breeding cats with signs to be desexed. 
* A requirement for periodic X-rays of breeding cats and comparison of X-ray evidence with clinical symptoms, possibly leading to a requirement that cats with a specified degree of skeletal change to be desexed.
* Requesting the agreement of pet owners to be periodically contacted by the NZCF or by a researcher, to provide reports about the health of their cat. 
* All information to be reported/submitted to the BSAC to allow information to be collated to give an overall picture of FOCD in Scottish Folds in NZ.
* Requirements to be in place for a minimum of 5 years to enable tracking of the health of Folds over time.

===Popularity===
Despite warnings from organisation such as GCCF ("we strongly advise members of the public not to try to acquire cats of this breed"<ref name="GCCF-health" />), the distinctive physical traits of the Scottish Fold, combined with their reputation as unusually loving companions, make Folds highly sought-after pets, with Fold kittens typically costing considerably more than kittens of more common breeds.<ref name="PetPlace">{{cite web |url= http://www.petplace.com/cats/choosing-a-scottish-fold/page1.aspx |title=Choosing a Scottish Fold |work=Pet Place |access-date=3 October 2009}}</ref> Scottish folds are also popular among celebrities, one of them being American singer [[Taylor Swift]], who owns two Scottish fold cats named Meredith Grey (after [[Meredith Grey|the titular character]] of the medical drama series ''[[Grey's Anatomy]]''), and [[Olivia Benson (cat)|Olivia Benson]] (after [[Olivia Benson|the protagonist]] of the police drama series ''[[Law & Order: Special Victims Unit]]'').<ref name="billboard">{{cite magazine |last1=Dailey |first1=Hannah |title=Taylor Swift's Cat Olivia Benson Is Reportedly Worth $97 Million |url= https://www.billboard.com/music/music-news/taylor-swift-cat-olivia-benson-worth-97-million-1235193860/ |magazine=Billboard |publisher=Penske Media Corporation |access-date=31 January 2023}}</ref>

==Health==
[[Polycystic kidney disease]] (PKD) is prevalent in the Scottish Fold.<ref>{{cite journal | last1=Shitamori | first1=Fumitaka | last2=Nonogaki | first2=Ayaka | last3=Motegi | first3=Tomoki | last4=Matsumoto | first4=Yuki | last5=Sakamoto | first5=Mika | last6=Tanizawa | first6=Yasuhiro | last7=Nakamura | first7=Yasukazu | last8=Yonezawa | first8=Tomohiro | last9=Momoi | first9=Yasuyuki | last10=Maeda | first10=Shingo | title=Large-scale epidemiological study on feline autosomal dominant polycystic kidney disease and identification of novel PKD1 gene variants | journal=Journal of Feline Medicine and Surgery | publisher=SAGE Publications | volume=25 | issue=7 | year=2023 | article-number=1098612X231185393 | issn=1098-612X | doi=10.1177/1098612x231185393 | doi-access=free | pmid=37489504 | pmc=10812055 }}</ref> A study in Japan of cats suspected to have kidney problems found that 54% of tested Scottish Fold cats had the PKD1 mutation, which is responsible for PKD.<ref>{{cite journal |last1=Sato |first1=R. |last2=Uchida |first2=N. |last3=Kawana |first3=Y. |last4=Tozuka |first4=M. |last5=Kobayashi |first5=S. |last6=Hanyu |first6=N. |last7=Konno |first7=Y. |last8=Iguchi |first8=Aiko |last9=Yamasaki |first9=Yayoi |last10=Kuramochi |first10=Konomi |last11=Yamasaki |first11=Masahiro |title=Epidemiological evaluation of cats associated with feline polycystic kidney disease caused by the feline PKD1 genetic mutation in Japan |journal=The Journal of Veterinary Medical Science |date=2019 |volume=81 |issue=7 |pages=1006–11 |pmid=31155548 |doi=10.1292/jvms.18-0309 |pmc=6656814 }}</ref>

A study in Japan found two genes linked to [[hypertrophic cardiomyopathy]] in the Scottish Fold population.<ref>{{cite journal | last1=Akiyama | first1=Noriyoshi | last2=Suzuki | first2=Ryohei | last3=Saito | first3=Takahiro | last4=Yuchi | first4=Yunosuke | last5=Ukawa | first5=Hisashi | last6=Matsumoto | first6=Yuki | title=Presence of known feline ALMS1 and MYBPC3 variants in a diverse cohort of cats with hypertrophic cardiomyopathy in Japan | journal=PLOS ONE | publisher=Public Library of Science (PLoS) | volume=18 | issue=4 | date=2023-04-18 | issn=1932-6203 | doi=10.1371/journal.pone.0283433 | doi-access=free | article-number=e0283433| pmid=37071642 | pmc=10112785 | bibcode=2023PLoSO..1883433A }}</ref>

===Osteochondrodysplasia===
A defect of [[Ear|aural]] [[cartilage]] gives the Scottish Fold the characteristic appearance. This cartilage defect is caused by an [[autosomal]] [[dominant gene]]. This mutation also causes a shortened and stiff tail that lacks rigidity. It also causes a [[skeletal dysplasia]] known as osteochondrodysplasia. All Scottish Fold cats develop [[arthritis]]: [[heterozygous]] cats develop a progressive form of arthritis and [[homozygous]] cats develop a severe arthritis much quicker than heterozygous cats.  Near the [[Hock (anatomy)|tarsal]] and [[metatarsal]] joints [[exostosis]] forms in kittens with the condition. [[Endochondral ossification]] is retarded and [[metatarsal]] and [[metacarpal]] bones fail to reach full length and develop abnormally result in improper shapes for the bones. Treatment is possible with either [[palliative radiation]] and surgery, which can be either excising the exostoses or a bilateral [[pantarsal arthrodesis]] can alleviate [[lameness]]; however, given all fold cats will become affected the only solution is the cessation of breeding of affected cats.<ref name="orthopaedics">{{cite book | last1=Scott | first1=Harry | last2=Marti | first2=Juan M | last3=Witte | first3=Philip | title=Feline Orthopaedics | publisher=CRC Press | publication-place=Boca Raton | date=August 2021 | isbn=978-1-4987-6497-1 | page=107}}</ref>

In a 2021 study,<ref>{{Cite journal |doi=10.1007/s00439-021-02337-5 |pmid=34406467 |title=Radiographical Survey of Osteochondrodysplasia in Scottish Fold Cats caused by the TRPV4 gene variant |date=2021 |last1=Rorden |first1=Chris |last2=Griswold |first2=Marilee C. |last3=Moses |first3=Nan |last4=Berry |first4=Clifford R. |last5=Keller |first5=G. Gregory |last6=Rivas |first6=Rudy |last7=Flores-Smith |first7=Helen |last8=Shaffer |first8=Lisa G. |last9=Malik |first9=Richard |journal=[[Human Genetics (journal)|Human Genetics]] |volume=140 |issue=11 |pages=1525–34 |s2cid=237198301}}</ref> four radiologists, [[Blinded experiment|blinded]] to the ear phenotype, assessed radiographs of 22 Scottish Fold/Straight cats. All cats were genotyped showing the heterozygous mutation in all folded ear cats but not in straight cats. Each reviewer gave on average the folded ear cats a worse "severity score", however the images showed much milder signs than previously published. The authors state that the severity of OCD in heterozygous cats is very variable and subtle. This could be due to other modifier genes or nurture (climate, diet, exercise). So it was shown that the least affected folded ear cat was given identical or less score than the highest rated straight ear cat.

In a 2020 case study,<ref>{{Cite journal |doi=10.1292/jvms.20-0299 |pmc=7804039 |pmid=33162427 |title=Osteochondrodysplasia in Scottish Fold cross-breed cats |date=2020 |last1=Takanosu |first1=Masamine |last2=Hattori |first2=Yuki |journal=The Journal of Veterinary Medical Science |volume=82 |issue=12 |pages=1769–72}}</ref> two Scottish Fold mixed cats with severe [[exostosis]] in the hind leg are described. Both cats were homozygous for the ''Trpv4'' mutation, assuming the parental cats had both the c.1024G>T mutation in the ''TrpV4'' gene. This reinforces the hypothesis that mostly homozygous Scottish Folds are severely affected.<ref>{{cite journal |pmid=18339089 |date=2008 |last1=Takanosu |first1=M. |last2=Takanosu |first2=T. |last3=Suzuki |first3=H. |last4=Suzuki |first4=K. |title=Incomplete dominant osteochondrodysplasia in heterozygous Scottish Fold cats |journal=The Journal of Small Animal Practice |volume=49 |issue=4 |pages=197–9 |doi=10.1111/j.1748-5827.2008.00561.x}}</ref> On the other hand it is concerning that still Scottish Fold cats are bred with each other,  also breeding with other cat strains with skeletal abnormalities ([[Munchkin cat|Munchkin]], [[American Curl]]) should be avoided.

In a large retrospective Australian study <ref>{{cite journal |vauthors=Velie BD, Milden T, Miller H, Haase B |title=An estimation of osteochondrodysplasia prevalence in Australian Scottish Fold cats: a retrospective study using VetCompass Data |journal=BMC Vet Res |volume=19 |issue=1 |article-number=252 |date=November 2023 |pmid=38031079 |doi=10.1186/s12917-023-03811-0 |doi-access=free |pmc=10685627 }}</ref> over 30,000 patient records from veterinary clinics were searched for specific keywords to look for the occurrence of OCD in Scottish Fold cats. Of 1131 Scottish Folds, 12 were detected with OCD (1.1%) and 5.7% were suspected of OCD. 

In a study by Sartore et al.<ref>{{cite journal |vauthors=Sartore S, Moretti R, Piras LA, Longo M, Chessa S, Sacchi P |title=Osteochondrodysplasia and the c.1024G>T variant of TRPV4 gene in Scottish Fold cats: genetic and radiographic evaluation |journal=J Feline Med Surg |volume=25 |issue=12 |article-number=1098612X231211763 |date=December 2023 |pmid=38055304 |doi=10.1177/1098612X231211763 |pmc=10811760 }}</ref>, in which folded-eared cats were genetically analyzed and only one specific gene variant (c.1024G>T) was examined, it was found that 1 out of 12 cats showed signs of OCD. The authors speculate that it is not just this mutation in the ''Trpv4'' gene that is responsible for the development of OCD.

Because heterozygous Scottish Folds also develop [[Progressive disease|progressive]] arthritis of varying severity, some researchers recommend abandoning the breeding of Fold cats entirely.<ref name="AustraliaVetJournal">{{cite journal |last1=Malik |first1=R. |last2=Allan |first2=G.S. |last3=Howlett |first3=C.R. |last4=Thompson |first4=D.E. |last5=James |first5=G. |last6=McWhirter |first6=C. |last7=Kendall |first7=K. |title=Osteochondrodysplasia in Scottish Fold cats |journal=[[Australian Veterinary Journal]] |date=February 1999 |volume=77 |issue=2 |pages=85–92 |doi=10.1111/j.1751-0813.1999.tb11672.x |pmid=10078353}}</ref><ref>{{cite web |url= http://www.vin.com/proceedings/Proceedings.plx?CID=WSAVA2003&PID=6652&O=Generic |title=Genetic Disorders of Cats |last=Malik |first=Richard |date=2003 |publisher=World Small Animal Veterinary Association |work=World Congress Proceedings, 2003 |access-date=20 December 2009}}</ref>

== In popular culture ==

=== ''The Cat Who Went to Paris'' ===
The short novel ''[[The Cat Who Went to Paris]]'' by [[Peter Gethers]] features "the most famous Scottish Fold" according to Grace Sutton of The Cat Fanciers' Association.{{r|CFA}} The book – and the two that followed – document the life of Gethers and his Fold, Norton, from their first meeting to Norton's eventual death and Gethers' experiences after the loss.

==See also==
* {{Portal inline|Cats}}
* {{Portal inline|Scotland}}
* [[American Curl]], a breed with ears curving up and back, somewhat opposite to the Scottish Fold
* [[List of cat body-type mutations|Cat body type genetic mutations]]
* [[List of Scottish breeds]]

==References==
{{Reflist|30em}}

==External links==
{{Commons category|Scottish Fold cats}}
* [http://www.cfa.org/Breeds/BreedsSthruT/ScottishFold.aspx CFA breed Profile] {{Webarchive|url=https://web.archive.org/web/20190717035353/http://www.cfa.org/Breeds/BreedsSthruT/ScottishFold.aspx |date=17 July 2019 }}
* [https://web.archive.org/web/20120319161612/http://www.ufaw.org.uk/OSTEOCHONDRODYSPLASIASCOTTISHFOLD.php Osteochondrodysplasia in Scottish Fold]

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