Editing Achondroplasia

{{Short description|Genetic condition, the most common form of dwarfism}}
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{{Use dmy dates|date=December 2020}}

{{Infobox medical condition (new)
| name            = Achondroplasia
| image           = Jason Acuña - Wee-Man - Waterfront Marriott, Portland, Oregon - August 15, 2009 - Full Body.jpg
| caption         = [[Jason Acuña|Jason "Wee Man" Acuña]], an American actor and stunt performer with achondroplasia
| width           = 150px
| field           = [[Medical genetics]]
| pronounce       = {{IPAc-en|eɪ|ˌ|k|ɒ|n|d|r|ə|ˈ|p|l|eɪ|z|i|ə|,_|ə|-|,_|-|ˈ|p|l|eɪ|ʒ|(|i|)|ə|audio=LL-Q1860 (eng)-Flame, not lame-Achondroplasia.wav}}{{refn|{{cite encyclopedia |url=http://www.lexico.com/definition/Achondroplasia |archive-url=https://web.archive.org/web/20191211194209/https://www.lexico.com/definition/achondroplasia |url-status=dead |archive-date=2019-12-11 |title=Achondroplasia |dictionary=[[Lexico]] UK English Dictionary |publisher=[[Oxford University Press]]}}}}{{refn|{{MerriamWebsterDictionary|Achondroplasia}}}}
| symptoms        = Short arms and legs, enlarged head, prominent forehead<ref name=GHR2012/>
| complications   = [[Ear infections]], [[Lordosis#Lumbar hyperlordosis|hyperlordosis]], [[back pain]], [[spinal stenosis]], [[hydrocephalus]]<ref name=GHR2012/>
| onset           =
| duration        =
| types           =
| causes          = Genetic ([[autosomal dominant]] mutation in the ''[[FGFR3]]'' gene)<ref name=GHR2012/>
| risks           = [[Paternal age]]<ref name=Lancet2007 /><ref name=GHR2012/>
| diagnosis       = Based on symptoms, [[genetic testing]] if uncertain<ref name=Pau2012/>
| differential    = [[Hypochondroplasia]], [[thanatophoric dysplasia]], [[cartilage-hair hypoplasia]], [[pseudoachondroplasia]]<ref name=Pau2012/>
| prevention      =
| treatment       = [[Support groups]], [[growth hormone therapy]], treatment of complications<ref name=Pau2012/>
| medication      =
| prognosis       =
| frequency       = 1 in 27,500 people<ref name=GHR2012/>
| deaths          =
}}

<!-- Definition and symptoms -->
'''Achondroplasia''' is a [[genetic disorder]] with an autosomal dominant pattern of inheritance whose primary feature is [[dwarfism]].<ref name="GHR2012">{{cite web |date=May 2012 |title=Achondroplasia |url=https://ghr.nlm.nih.gov/condition/achondroplasia |access-date=12 December 2017 |website=Genetics Home Reference |language=en}}</ref> It is the most common cause of dwarfism<ref name="Lancet2007" /> and affects about 1 in 27,500 people.<ref name="GHR2012" /> In those with the condition, the [[Rhizomelia|arms and legs are short]], while the [[torso]] is typically of normal length.<ref name=GHR2012/> Those affected have an average adult height of {{convert|131|cm|ftin}} for males and {{convert|123|cm|ft|0}} for females.<ref name=GHR2012/> Other features can include an [[Macrocephaly|enlarged head]] with [[Skull bossing|prominent forehead (frontal bossing)]]<ref name="GHR2012" /> and underdevelopment of the midface (midface hypoplasia).<ref name="onlinelibrary.wiley.com">{{cite journal |last1=White |first1=Klane K. |last2=Bompadre |first2=Viviana |last3=Goldberg |first3=Michael J. |last4=Bober |first4=Michael B. |last5=Campbell |first5=Jeffrey W. |last6=Cho |first6=Tae-Joon |last7=Hoover-Fong |first7=Julie |last8=Mackenzie |first8=William |last9=Parnell |first9=Shawn E. |last10=Raggio |first10=Cathleen |last11=Rapoport |first11=David M. |last12=Spencer |first12=Samantha A. |last13=Savarirayan |first13=Ravi |date=2016-01-01 |title=Best practices in the evaluation and treatment of foramen magnum stenosis in achondroplasia during infancy |url=https://onlinelibrary.wiley.com/doi/10.1002/ajmg.a.37394 |journal=American Journal of Medical Genetics Part A |language=en |volume=170 |issue=1 |pages=42–51 |doi=10.1002/ajmg.a.37394 |pmid=26394886 |s2cid=22430204 |issn=1552-4825}}</ref> Complications can include [[sleep apnea]] or recurrent [[ear infections]].<ref name=GHR2012/> Achondroplasia includes the extremely rare [[short-limb skeletal dysplasia with severe combined immunodeficiency]].

Achondroplasia is caused by a mutation in the [[fibroblast growth factor receptor 3]] (''FGFR3'') [[gene]] that results in its [[protein]] being [[Gain-of-function|overactive]].<ref name=GHR2012/> Achondroplasia results in impaired endochondral bone growth (bone growth within cartilage).<ref name="Achondroplasia: A comprehensive cli">{{cite journal|doi=10.1186/s13023-018-0972-6|title=Achondroplasia: A comprehensive clinical review|year=2019|last1=Pauli|first1=Richard M.|journal=Orphanet Journal of Rare Diseases|volume=14|issue=1|page=1|pmid=30606190|pmc=6318916 |doi-access=free}}</ref> The disorder has an [[autosomal dominant]] mode of inheritance, meaning only one mutated copy of the gene is required for the condition to occur.<ref name=NIH2016>{{cite web|title=Achondroplasia|url=https://rarediseases.info.nih.gov/diseases/8173/achondroplasia|website=Genetic and Rare Diseases Information Center (GARD) – an NCATS Program|access-date=12 December 2017|language=en|date=2016}}</ref> About 80% of cases occur in children of parents without the disease, and result from a new (''de novo'', or sporadic) mutation, which most commonly originates as a spontaneous change during [[spermatogenesis]].<ref name="Pau2012" /> The rest are inherited from a parent with the condition.<ref name=GHR2012/> The risk of a new mutation increases with the [[Paternal age effect#Single-gene disorders|age of the father]].<ref name=Lancet2007 /> In families with two affected parents, children who inherit both affected genes typically [[Recessive lethal|die before birth or in early infancy]] from breathing difficulties.<ref name=GHR2012/> The condition is generally diagnosed based on the clinical features but may be confirmed by [[genetic testing]].<ref name=Pau2012>{{cite journal|last1=Pauli|first1=RM|last2=Adam|first2=MP|last3=Ardinger|first3=HH|last4=Pagon|first4=RA|last5=Wallace|first5=SE|last6=Bean|first6=LJH|last7=Mefford|first7=HC|last8=Stephens|first8=K|last9=Amemiya|first9=A|last10=Ledbetter|first10=N|title=Achondroplasia|journal=GeneReviews|date=2012|pmid=20301331}}</ref> Mutations in FGFR3 also cause achondroplasia related conditions including hypochondroplasia and SADDAN (severe achondroplasia with developmental delay and acanthosis nigricans), a rare disorder of bone growth characterized by skeletal, brain, and skin abnormalities resulting in severe [[short-limb skeletal dysplasia with severe combined immunodeficiency]].<ref>{{Citation |last=Legare |first=Janet M. |title=Achondroplasia |date=1993 |url=http://www.ncbi.nlm.nih.gov/books/NBK1152/ |work=GeneReviews® |editor-last=Adam |editor-first=Margaret P. |access-date=2023-12-15 |place=Seattle (WA) |publisher=University of Washington, Seattle |pmid=20301331 |editor2-last=Feldman |editor2-first=Jerry |editor3-last=Mirzaa |editor3-first=Ghayda M. |editor4-last=Pagon |editor4-first=Roberta A.}}</ref>

Treatments include small molecule therapy with a C-natriuretic peptide analog ([[vosoritide]]), approved to improve growth velocity in children with achondroplasia based on results in Phase 3 human trials, although its long-term effects are unknown.<ref name=":0">{{cite journal |last1=Savarirayan |first1=Ravi |last2=Tofts |first2=Louise |last3=Irving |first3=Melita |last4=Wilcox |first4=William |last5=Bacino |first5=Carlos A. |last6=Hoover-Fong |first6=Julie |last7=Font |first7=Rosendo Ullot |last8=Harmatz |first8=Paul |last9=Rutsch |first9=Frank |last10=Bober |first10=Michael B. |last11=Polgreen |first11=Lynda E. |last12=Ginebreda |first12=Ignacio |last13=Mohnike |first13=Klaus |last14=Charrow |first14=Joel |last15=Hoernschemeyer |first15=Daniel |date=5 September 2020 |title=Once-daily, subcutaneous vosoritide therapy in children with achondroplasia: a randomised, double-blind, phase 3, placebo-controlled, multicentre trial |journal=The Lancet |volume=396 |issue=10252 |pages=684–692 |doi=10.1016/S0140-6736(20)31541-5 |pmid=32891212 |s2cid=221472752 |last16=Ozono |first16=Keiichi |last17=Alanay |first17=Yasemin |last18=Arundel |first18=Paul |last19=Kagami |first19=Shoji |last20=Yasui |first20=Natsuo |last21=White |first21=Klane K. |last22=Saal |first22=Howard M. |last23=Leiva-Gea |first23=Antonio |last24=Luna-González |first24=Felipe |last25=Mochizuki |first25=Hiroshi |last26=Basel |first26=Donald |last27=Porco |first27=Dania M. |last28=Jayaram |first28=Kala |last29=Fisheleva |first29=Elena |last30=Huntsman-Labed |first30=Alice |last31=Day |first31=Jonathan}}</ref> [[Growth hormone therapy]] may also be used.<ref name="Pau2012" /> Efforts to treat or prevent complications such as [[obesity]], [[hydrocephalus]], [[obstructive sleep apnea]], [[middle ear infections]] or [[spinal stenosis]] may be required.<ref name="Pau2012" /> [[Support groups]] support people with achondroplasia, including the [https://www.lpaonline.org Little People of America (LPA)] and [https://growingstronger.org Growing Stronger]. Nonprofit physician organizations also exist to disseminate information about treatment and management options, including development of [https://www.skeletaldysplasia.org/patients patient resources].

== Signs and symptoms ==
* Disproportionate dwarfism
* Shortening of the proximal limbs (called [[rhizomelic]] shortening)
* Short fingers and toes, with "trident hands" (short hands with stubby fingers, and a separation between the middle and ring fingers – reminiscent of a trident on fetal ultrasound)<ref>{{cite web |author=<!--Not stated--> |title=Trident hand |url=http://radiopaedia.org/articles/trident-hand |access-date=31 May 2022 |website=Radiopaedia}}</ref>
* Large head with prominent forehead [[frontal bossing]]
* Small midface with a flattened nasal bridge
* Spinal [[kyphosis]] (convex curvature) or [[lordosis]] (concave curvature)
* [[Varus deformity|Varus]] (bowleg) or [[Valgus deformity|valgus]] (knock knee) deformities
* Frequent [[Otitis|ear infections]] (due to [[Eustachian tube]] blockages), sleep [[apnea]] (which can be [[Central sleep apnea|central]] or [[Obstructive sleep apnea|obstructive]]), and [[hydrocephalus]]

=== Complications ===
==== Children ====
{{main|Achondroplasia in children}}
Children with achondroplasia often have less muscle tone; because of this it is common for them to have delayed walking and motor skills. It is also common for children to have bowed legs, scoliosis, lordosis, arthritis, issues with joint flexibility, breathing problems, ear infections, and crowded teeth.<ref>{{cite web|url=https://kidshealth.org/en/parents/dwarfism.html|title=Dwarfism|website=kidshealth.org|language=en|access-date=26 September 2018}}</ref> These issues can be treated with surgery, braces, or physical therapy.{{citation needed|date=June 2024}}

Hydrocephalus is a severe effect associated with achondroplasia in children. This condition occurs when cerebrospinal fluid is not able to flow in and out of the skull because of how the spine narrows.<ref>{{cite web|url=https://rarediseases.info.nih.gov/diseases/8173/achondroplasia|title=Achondroplasia {{!}} Genetic and Rare Diseases Information Center (GARD) – an NCATS Program|website=rarediseases.info.nih.gov|language=en|access-date=26 September 2018}}</ref> This fluid build up is associated with an enlarged head, vomiting, lethargy, headaches, and irritability.<ref>{{cite news|url=https://www.hopkinsmedicine.org/neurology_neurosurgery/centers_clinics/pediatric_neurosurgery/conditions/achondroplasia.html|title=Achondroplasia {{!}} Johns Hopkins Pediatric Neurosurgery|last=Kieffer|first=Sara|access-date=26 September 2018|language=en}}</ref> A [[Cerebral shunt|shunt surgery]] is commonly performed to treat this condition, but an endoscopic third ventriculostomy can also be done.<ref>{{cite web|url=https://www.mayoclinic.org/diseases-conditions/hydrocephalus/diagnosis-treatment/drc-20373609|title=Hydrocephalus – Diagnosis and treatment – Mayo Clinic|website=mayoclinic.org|language=en|access-date=26 September 2018}}</ref>

==== Adults ====
Adults with achondroplasia often face issues with obesity and sleep apnea. It is also typical for adults to experience numbness or tingling in their legs because of nerve compression.{{citation needed|date=June 2024}}

Some research has found that adults with achondroplasia may also experience [[psychosocial]] complications, usually associated with short stature.<ref name="Achondroplasia: A comprehensive cli"/><ref>{{cite journal|doi=10.1080/09638288.2021.1963853|title=Quality of life, physical functioning, and psychosocial function among patients with achondroplasia: A targeted literature review|year=2021|last1=Constantinides|first1=Constantinos|last2=Landis|first2=Sarah H.|last3=Jarrett|first3=James|last4=Quinn|first4=Jennifer|last5=Ireland|first5=Penelope J.|journal=Disability and Rehabilitation|volume=44 |issue=21 |pages=6166–6178|pmid=34403286|s2cid=237198129|doi-access=free}}</ref>

Pregnancy in women with achondroplasia is considered higher risk. Women with achondroplasia generally have their babies delivered through C-sections to prevent complications that could occur with a natural birth.<ref>{{cite news|url=https://www.betterhealth.vic.gov.au/health/conditionsandtreatments/dwarfism|title=Dwarfism|last=Services|first=Department of Health & Human|access-date=26 September 2018|language=en}}</ref> Intelligence and life span are usually near normal, although craniocervical junction compression increases the risk of death in infancy.<ref>{{cite web | url=https://pubmed.ncbi.nlm.nih.gov/20301331/ | pmid=20301331 | date=1993 | last1=Adam | first1=M. P. | last2=Feldman | first2=J. | last3=Mirzaa | first3=G. M. | last4=Pagon | first4=R. A. | last5=Wallace | first5=S. E. | author6=Bean LJH | last7=Gripp | first7=K. W. | last8=Amemiya | first8=A. | last9=Legare | first9=J. M. | title=Achondroplasia | publisher=University of Washington, Seattle}}</ref>

== Causes ==
[[File:Autosomal dominant - en.svg|thumb|Autosomal dominant inheritance]]
[[File:Gould Pyle 161.jpg|thumb|Mother and child with achondroplasia with unaffected father, showing inheritance]]
Achondroplasia is caused by a mutation in [[fibroblast growth factor receptor 3]] (''FGFR3'') gene.<ref>{{cite web|url=https://www.genome.gov/19517823/learning-about-achondroplasia/|title=Learning About Achondroplasia|website=National Human Genome Research Institute (NHGRI)|language=en-US|access-date=26 September 2018}}</ref> This gene encodes a protein called fibroblast growth factor receptor 3, which contributes to the production of collagen and other structural components in tissues and bones.<ref>{{cite web|url=https://ghr.nlm.nih.gov/gene/FGFR3|title=FGFR3 gene|last=Reference|first=Genetics Home|website=Genetics Home Reference|language=en|access-date=26 September 2018}}</ref> When the FGFR3 gene is mutated it interferes with how this protein interacts with growth factors leading to complications with bone production. Cartilage is not able to fully develop into bone, causing the individual to be disproportionately shorter in height.<ref>{{cite journal |last1=Horton |first1=William A |last2=Hall |first2=Judith G |last3=Hecht |first3=Jacqueline T |date=July 2007 |title=Achondroplasia |url=http://dx.doi.org/10.1016/s0140-6736(07)61090-3 |journal=The Lancet |volume=370 |issue=9582 |pages=162–172 |doi=10.1016/s0140-6736(07)61090-3 |pmid=17630040 |s2cid=208788746 |issn=0140-6736}}</ref>

In normal development, ''FGFR3'' has a negative regulatory effect on bone growth. In achondroplasia, the mutated form of the receptor is constitutively active, and this leads to severely shortened bones. This is an example of a [[Gain-of-function mutation|gain of function]] mutation. The effect is [[Dominance (genetics)|genetically dominant]], with one variant of the ''FGFR3'' gene being sufficient to cause achondroplasia, while two copies of the mutant gene are invariably fatal ([[Lethal allele|recessive lethal]]) before or shortly after birth. This occurs due to respiratory failure from an underdeveloped ribcage.<ref name="GHR2012" /> People with achondroplasia are often born to parents that do not have the condition due to [[Mutation#Spontaneous mutation|spontaneous mutation]].<ref name="pmid17950653">{{cite journal|vauthors=Richette P, Bardin T, Stheneur C|title=Achondroplasia: From genotype to phenotype|journal=Joint Bone Spine|volume= 75|issue=  2| pages = 125–30|year=2007|pmid=17950653|doi=10.1016/j.jbspin.2007.06.007}}</ref>

Where achondroplasia is inherited, its pattern is autosomal dominant. In couples where one partner has achondroplasia there is a 50% chance of passing the disorder on to their child every pregnancy. In situations where both parents have achondroplasia there is a 50% chance the child will have achondroplasia, 25% chance the child will not, and a 25% chance that the child will inherit the gene from both parents resulting in ''double [[Dominance (genetics)|dominance]]'' and leading to lethal bone [[dysplasia]].<ref>{{cite news|url=https://www.marchofdimes.org/complications/achondroplasia.aspx|title=Achondroplasia|access-date=26 September 2018|language=en-US}}</ref>

Studies have demonstrated that new gene mutations for achondroplasia are exclusively inherited from the father and occur during [[spermatogenesis]]; it has been theorized that sperm carrying the mutation in FGFR3 have a selective advantage over sperm with normal FGFR3.<ref name=Lancet2007>{{cite journal|last1=Horton|first1=William A|last2=Hall|first2=Judith G|last3=Hecht|first3=Jacqueline T|title=Achondroplasia|journal=The Lancet|date=July 2007|volume=370|issue=9582|pages=162–172|doi=10.1016/S0140-6736(07)61090-3|pmid=17630040|s2cid=208788746}}</ref> The frequency of mutations in sperm leading to achondroplasia increases in proportion to paternal age, as well as in proportion to exposure to [[ionizing radiation]].<ref name="pmid16766665">{{cite journal| vauthors=Wyrobek AJ, Eskenazi B, Young S, Arnheim N, Tiemann-Boege I, Jabs EW, Glaser RL, Pearson FS, Evenson D| title=Advancing age has differential effects on DNA damage, chromatin integrity, gene mutations, and aneuploidies in sperm| journal= [[Proceedings of the National Academy of Sciences of the United States of America]]| volume=103| issue=25| pages=9601–9606| year=2006| doi=10.1073/pnas.0506468103| pmc=1480453| pmid = 16766665| bibcode=2006PNAS..103.9601W| doi-access=free}}</ref> The occurrence rate of achondroplasia in the children of fathers over 50&nbsp;years of age is 1&nbsp;in 1,875, compared to 1&nbsp;in 15,000 in the general population.<ref name="pmid23912310">{{cite journal|last1=Kovac|first1=Jason R|last2=Addai|first2=Josephine|last3=Smith|first3=Ryan P|last4=Coward|first4=Robert M|last5=Lamb|first5=Dolores J|last6=Lipshultz|first6=Larry I|title=The effects of advanced paternal age on fertility|journal=Asian Journal of Andrology|date=November 2013|volume=15|issue=6|pages=723–728|doi=10.1038/aja.2013.92|pmid=23912310|pmc=3854059}}</ref> Research by [[urologist]] Harry Fisch of the Male Reproductive Center at [[Columbia Presbyterian Hospital]] in 2013 indicated that in humans this defect may be exclusively inherited from the father and becomes increasingly probable with paternal age, specifically males reproducing after 35.<ref name="Fisch2013">{{cite book|author=Harry Fisch|title=The Male Biological Clock: The Startling News About Aging, Sexuality, and Fertility in Men|url=https://books.google.com/books?id=BxqFgFunQ18C&pg=PT11|date=24 September 2013|publisher=Simon and Schuster|isbn=978-1-4767-4082-9|pages=11–}}</ref>

There are two other syndromes with a genetic basis similar to achondroplasia: [[hypochondroplasia]] and [[thanatophoric dysplasia]].

== Diagnosis ==
[[File:Las Meninas detail.jpg|thumb|upright=1.6|Detail of ''[[Las Meninas]]'' by [[Diego Velázquez]] (1656), showing Maribarbola and Nicolasito Pertusato (right), achondroplastic dwarfs in the entourage of [[Margaret Theresa of Spain|Infanta Margarita]]]]

Achondroplasia can be detected before birth by [[Prenatal testing|prenatal]] [[ultrasound]], although signs are often subtle and not apparent before the 24th week of pregnancy.<ref>{{cite journal|doi=10.1038/s41574-021-00595-x|quote="Ultrasound findings of achondroplasia are generally not apparent until 24 weeks of gestation and are often quite subtle."|title=International Consensus Statement on the diagnosis, multidisciplinary management and lifelong care of individuals with achondroplasia|year=2021|last1=Savarirayan|first1=Ravi|last2=Ireland|first2=Penny|last3=Irving|first3=Melita|last4=Thompson|first4=Dominic|last5=Alves|first5=Inês|last6=Baratela|first6=Wagner A. R.|last7=Betts|first7=James|last8=Bober|first8=Michael B.|last9=Boero|first9=Silvio|last10=Briddell|first10=Jenna|last11=Campbell|first11=Jeffrey|last12=Campeau|first12=Philippe M.|last13=Carl-Innig|first13=Patricia|last14=Cheung|first14=Moira S.|last15=Cobourne|first15=Martyn|last16=Cormier-Daire|first16=Valérie|last17=Deladure-Molla|first17=Muriel|last18=Del Pino|first18=Mariana|last19=Elphick|first19=Heather|last20=Fano|first20=Virginia|last21=Fauroux|first21=Brigitte|last22=Gibbins|first22=Jonathan|last23=Groves|first23=Mari L.|last24=Hagenäs|first24=Lars|last25=Hannon|first25=Therese|last26=Hoover-Fong|first26=Julie|last27=Kaisermann|first27=Morrys|last28=Leiva-Gea|first28=Antonio|last29=Llerena|first29=Juan|last30=MacKenzie|first30=William|journal=Nature Reviews Endocrinology|volume=18 |issue=3 |pages=173–189 |pmid=34837063|s2cid=244638495|display-authors=1|doi-access=free}}</ref> A DNA test can be performed before birth to detect [[Zygosity#Homozygous|homozygosity]], wherein two copies of the mutant gene are inherited, a lethal condition leading to [[stillbirths]]. Postnatal diagnosis of achondroplasia is typically uncomplicated, involving an assessment of physical and radiographic features.<ref>{{cite journal|doi=10.1038/s41574-021-00595-x|quote="The postnatal diagnosis of achondroplasia is fairly straightforward. A combination of key clinical (that is, macrocephaly, short limbed-short stature with rhizomelia and redundant skin folds) and radiographic (that is, characteristic pelvis with short and square ilia, narrow sacro-sciatic notches and narrowing interpedicular distances in the lumbar vertebral spine progressing from L1 to L5) features enables accurate diagnosis in most people with achondroplasia."|title=International Consensus Statement on the diagnosis, multidisciplinary management and lifelong care of individuals with achondroplasia|year=2021|last1=Savarirayan|first1=Ravi|last2=Ireland|first2=Penny|last3=Irving|first3=Melita|last4=Thompson|first4=Dominic|last5=Alves|first5=Inês|last6=Baratela|first6=Wagner A. R.|last7=Betts|first7=James|last8=Bober|first8=Michael B.|last9=Boero|first9=Silvio|last10=Briddell|first10=Jenna|last11=Campbell|first11=Jeffrey|last12=Campeau|first12=Philippe M.|last13=Carl-Innig|first13=Patricia|last14=Cheung|first14=Moira S.|last15=Cobourne|first15=Martyn|last16=Cormier-Daire|first16=Valérie|last17=Deladure-Molla|first17=Muriel|last18=Del Pino|first18=Mariana|last19=Elphick|first19=Heather|last20=Fano|first20=Virginia|last21=Fauroux|first21=Brigitte|last22=Gibbins|first22=Jonathan|last23=Groves|first23=Mari L.|last24=Hagenäs|first24=Lars|last25=Hannon|first25=Therese|last26=Hoover-Fong|first26=Julie|last27=Kaisermann|first27=Morrys|last28=Leiva-Gea|first28=Antonio|last29=Llerena|first29=Juan|last30=MacKenzie|first30=William|journal=Nature Reviews Endocrinology|volume=18 |issue=3 |pages=173–189 |pmid=34837063|s2cid=244638495|display-authors=1|doi-access=free}}</ref>  Clinical features include megalocephaly, short limbs, prominent forehead, [[vertebral column|thoracolumbar]] kyphosis and mid-face hypoplasia.<ref name="BeattieChampion2004">{{cite book|title=Essential questions in paediatrics for MRCPCH.|year=2004|publisher=PasTest|location=Knutsford, Cheshire|isbn=978-1-901198-99-7|edition=1st|editor1=Beattie, R.M.|editor2=Champion, M.P.}}</ref> Complications like dental malocclusion, hydrocephalus and repeated otitis media can be observed.<ref name="BeattieChampion2004" /> The risk of death in infancy is increased due to the likelihood of compression of the spinal cord with or without upper airway obstruction.{{citation needed|date=September 2021}}

=== Radiologic findings ===
A skeletal survey is useful to confirm the diagnosis of achondroplasia. The skull is large, with a narrow [[foramen magnum]], and relatively small skull base. The vertebral bodies are short and flattened with relatively large intervertebral disk height, and there is congenitally narrowed [[spinal canal]]. The iliac wings are small and squared, with a narrow sciatic notch and horizontal acetabular roof.<ref name=elsobky2017>{{cite journal|last1=EL-Sobky|first1=TA|last2=Shawky|first2=RM|last3=Sakr|first3=HM|last4=Elsayed|first4=SM|last5=Elsayed|first5=NS|last6=Ragheb|first6=SG|last7=Gamal|first7=R|title=A systematized approach to radiographic assessment of commonly seen genetic bone diseases in children: A pictorial review.|journal= J Musculoskelet Surg Res|volume=1|issue=2|pages=25|date=15 November 2017|doi=10.4103/jmsr.jmsr_28_17|s2cid=79825711 |doi-access=free}}</ref><ref name="titleAchondroplasia Pelvis">{{cite web|url=http://www.stevensorenson.com/residents6/achondroplasia_pelvis.htm|title=Achondroplasia Pelvis|access-date=28 November 2007|archive-url=https://web.archive.org/web/20071022201339/http://stevensorenson.com/residents6/achondroplasia_pelvis.htm|archive-date=22 October 2007|url-status = dead}}</ref> The tubular bones are short and thick with [[metaphyseal]] cupping and flaring and irregular growth plates.<ref name=elsobky2017/> [[Fibular]] overgrowth is present. The hand is broad with short [[metacarpals]] and [[phalanges]], and a trident configuration. The ribs are short with cupped anterior ends.<ref name=elsobky2017/> If the [[radiographic]] features are not classic, a search for a different diagnosis should be entertained. Because of the extremely deformed bone structure, people with achondroplasia are often "[[Hypermobility (joints)|double jointed]]". The diagnosis can be made by fetal [[ultrasound]] by progressive discordance between the short [[femur]] length and biparietal diameter by age. The trident hand configuration can be seen if the fingers are fully extended.{{citation needed|date=September 2021}}

Another common characteristic of the syndrome is thoracolumbar [[Gibbus deformity|gibbus]] in infancy.<ref>{{cite journal|doi=10.1038/s41574-021-00595-x|quote="Spinal thoracolumbar kyphosis (gibbus) in infants with achondroplasia is common but should resolve when the child begins to mobilize."|title=International Consensus Statement on the diagnosis, multidisciplinary management and lifelong care of individuals with achondroplasia|year=2021|last1=Savarirayan|first1=Ravi|last2=Ireland|first2=Penny|last3=Irving|first3=Melita|last4=Thompson|first4=Dominic|last5=Alves|first5=Inês|last6=Baratela|first6=Wagner A. R.|last7=Betts|first7=James|last8=Bober|first8=Michael B.|last9=Boero|first9=Silvio|last10=Briddell|first10=Jenna|last11=Campbell|first11=Jeffrey|last12=Campeau|first12=Philippe M.|last13=Carl-Innig|first13=Patricia|last14=Cheung|first14=Moira S.|last15=Cobourne|first15=Martyn|last16=Cormier-Daire|first16=Valérie|last17=Deladure-Molla|first17=Muriel|last18=Del Pino|first18=Mariana|last19=Elphick|first19=Heather|last20=Fano|first20=Virginia|last21=Fauroux|first21=Brigitte|last22=Gibbins|first22=Jonathan|last23=Groves|first23=Mari L.|last24=Hagenäs|first24=Lars|last25=Hannon|first25=Therese|last26=Hoover-Fong|first26=Julie|last27=Kaisermann|first27=Morrys|last28=Leiva-Gea|first28=Antonio|last29=Llerena|first29=Juan|last30=MacKenzie|first30=William|journal=Nature Reviews Endocrinology|volume=18 |issue=3 |pages=173–189 |pmid=34837063|s2cid=244638495|display-authors=1|doi-access=free}}</ref>

== Treatment ==
There is no known cure for achondroplasia even though the cause of the mutation in the growth factor receptor has been found. Although used by those without achondroplasia to aid in growth, [[human growth hormone]] does not help people with achondroplasia, which involves a different hormonal pathway. Usually, the best results appear within the first and second year of therapy.<ref name="ReferenceA">{{cite journal|last1=Vajo|first1=Zoltan|last2=Francomano|first2=Clair A.|last3=Wilkin|first3=Douglas J.|title=The Molecular and Genetic Basis of Fibroblast Growth Factor Receptor 3 Disorders: The Achondroplasia Family of Skeletal Dysplasias, Muenke Craniosynostosis, and Crouzon Syndrome with Acanthosis Nigricans|journal=Endocrine Reviews|date=1 February 2000|volume=21|issue=1|pages=23–39|doi=10.1210/edrv.21.1.0387|pmid=10696568|url=https://zenodo.org/record/1236235|doi-access=free}}</ref> After the second year of growth hormone therapy, beneficial bone growth decreases,<ref>{{cite journal|last1=Aviezer|first1=David|last2=Golembo|first2=Myriam|last3=Yayon|first3=Avner|title=Fibroblast Growth Factor Receptor-3 as a Therapeutic Target for Achondroplasia - Genetic Short Limbed Dwarfism|journal=Current Drug Targets|date=30 June 2003|volume=4|issue=5|pages=353–365|doi=10.2174/1389450033490993|pmid=12816345}}</ref> so the therapy is not a satisfactory long-term treatment.<ref name="ReferenceA"/> As of December 2020, the treatment of achondroplasia with human growth hormone was approved only in Japan.<ref name="Legeai-Mallet">{{cite journal|doi=10.1016/j.bone.2020.115579|quote="One therapy offered to ACH patients is treatment with recombinant human growth (r-hGH) (approved today only in Japan)."|title=Novel therapeutic approaches for the treatment of achondroplasia|year=2020|last1=Legeai-Mallet|first1=Laurence|last2=Savarirayan|first2=Ravi|journal=Bone|volume=141|page=115579|pmid=32795681|s2cid=221133224|doi-access=free}}</ref>

A small-molecule drug [[vosoritide]] is used to improve growth velocity in children with achondroplasia,<ref name=":0" /> although its long-term effects are unknown. Vosoritide inhibits the activity of ''FGFR3''.<ref>{{cite journal |last1=Savarirayan |first1=Ravi |date=4 July 2019 |title=C-Type Natriuretic Peptide Analogue Therapy in Children with Achondroplasia |journal=New England Journal of Medicine |volume=381 |issue=1 |pages=25–35 |doi=10.1056/NEJMoa1813446 |pmid=31269546 |doi-access=free}}</ref> It has been gradually made available in different countries starting from 2021.

[[Limb-lengthening]] will increase the length of the legs and arms of someone with achondroplasia,<ref name="pmid17717461">{{cite journal|vauthors=Kitoh H, Kitakoji T, Tsuchiya H, Katoh M, Ishiguro N|title=Distraction osteogenesis of the lower extremity in patients that have achondroplasia/hypochondroplasia treated with transplantation of culture-expanded bone marrow cells and platelet-rich plasma|journal=J Pediatr Orthop|volume=27|issue=6|pages=629–34|year=2007|pmid=17717461|doi=10.1097/BPO.0b013e318093f523|s2cid=42226362}}</ref>  but little medical consensus exists regarding this practice. The age of surgery can vary from early childhood to adulthood.<ref>{{cite journal|doi=10.1038/s41574-021-00595-x|quote="Although evidence in this area is scarce, limb lengthening is advised in some countries and not recommended in others. ... The timing of limb lengthening varies and has been performed from early childhood to adult life in individuals with achondroplasia."|title=International Consensus Statement on the diagnosis, multidisciplinary management and lifelong care of individuals with achondroplasia|year=2021|last1=Savarirayan|first1=Ravi|last2=Ireland|first2=Penny|last3=Irving|first3=Melita|last4=Thompson|first4=Dominic|last5=Alves|first5=Inês|last6=Baratela|first6=Wagner A. R.|last7=Betts|first7=James|last8=Bober|first8=Michael B.|last9=Boero|first9=Silvio|last10=Briddell|first10=Jenna|last11=Campbell|first11=Jeffrey|last12=Campeau|first12=Philippe M.|last13=Carl-Innig|first13=Patricia|last14=Cheung|first14=Moira S.|last15=Cobourne|first15=Martyn|last16=Cormier-Daire|first16=Valérie|last17=Deladure-Molla|first17=Muriel|last18=Del Pino|first18=Mariana|last19=Elphick|first19=Heather|last20=Fano|first20=Virginia|last21=Fauroux|first21=Brigitte|last22=Gibbins|first22=Jonathan|last23=Groves|first23=Mari L.|last24=Hagenäs|first24=Lars|last25=Hannon|first25=Therese|last26=Hoover-Fong|first26=Julie|last27=Kaisermann|first27=Morrys|last28=Leiva-Gea|first28=Antonio|last29=Llerena|first29=Juan|last30=MacKenzie|first30=William|journal=Nature Reviews Endocrinology|volume=18 |issue=3 |pages=173–189 |pmid=34837063|s2cid=244638495|display-authors=1|doi-access=free}}</ref>

Research has also shown that introducing parents of children with achondroplasia to support and advocacy groups at the time of diagnosis can improve outcomes.<ref>{{cite journal|doi=10.1038/s41574-021-00595-x|quote="Introducing parents to advocacy and support groups has been proven beneficial."|title=International Consensus Statement on the diagnosis, multidisciplinary management and lifelong care of individuals with achondroplasia|year=2021|last1=Savarirayan|first1=Ravi|last2=Ireland|first2=Penny|last3=Irving|first3=Melita|last4=Thompson|first4=Dominic|last5=Alves|first5=Inês|last6=Baratela|first6=Wagner A. R.|last7=Betts|first7=James|last8=Bober|first8=Michael B.|last9=Boero|first9=Silvio|last10=Briddell|first10=Jenna|last11=Campbell|first11=Jeffrey|last12=Campeau|first12=Philippe M.|last13=Carl-Innig|first13=Patricia|last14=Cheung|first14=Moira S.|last15=Cobourne|first15=Martyn|last16=Cormier-Daire|first16=Valérie|last17=Deladure-Molla|first17=Muriel|last18=Del Pino|first18=Mariana|last19=Elphick|first19=Heather|last20=Fano|first20=Virginia|last21=Fauroux|first21=Brigitte|last22=Gibbins|first22=Jonathan|last23=Groves|first23=Mari L.|last24=Hagenäs|first24=Lars|last25=Hannon|first25=Therese|last26=Hoover-Fong|first26=Julie|last27=Kaisermann|first27=Morrys|last28=Leiva-Gea|first28=Antonio|last29=Llerena|first29=Juan|last30=MacKenzie|first30=William|journal=Nature Reviews Endocrinology|volume=18 |issue=3 |pages=173–189 |pmid=34837063|s2cid=244638495|display-authors=1|doi-access=free}}</ref> Several patient advocacy groups exist to support people with achondroplasia and their families.<ref>{{cite web |title=Associations |url=https://www.beyondachondroplasia.org/en/resources/patient-groups/associations |website=Beyond Achondroplasia |access-date=2 January 2022 |language=en-gb}}</ref> [https://www.skeletaldysplasia.org/patients Resources] are available to support patients and their caregivers with information that they can distribute to their physicians, who may not be familiar with the unique medical requirements of managing achondroplasia. Physician-oriented best practice guidelines are also available to guide physicians managing the spinal disorders,<ref>{{cite journal |last1=White |first1=Klane K. |last2=Bober |first2=Michael B. |last3=Cho |first3=Tae-Joon |last4=Goldberg |first4=Michael J. |last5=Hoover-Fong |first5=Julie |last6=Irving |first6=Melita |last7=Kamps |first7=Shawn E. |last8=Mackenzie |first8=William G. |last9=Raggio |first9=Cathleen |last10=Spencer |first10=Samantha A. |last11=Bompadre |first11=Viviana |last12=Savarirayan |first12=Ravi |last13=on behalf of the Skeletal Dysplasia Management Consortium |date=2020-12-24 |title=Best practice guidelines for management of spinal disorders in skeletal dysplasia |journal=Orphanet Journal of Rare Diseases |language=en |volume=15 |issue=1 |page=161 |doi=10.1186/s13023-020-01415-7 |pmid=32580780 |pmc=7313125 |issn=1750-1172 |doi-access=free}}</ref> foramen magnum stenosis,<ref name="onlinelibrary.wiley.com"/> craniofacial implications,<ref>{{cite journal |last1=on behalf of the Skeletal Dysplasia Management Consortium |last2=Savarirayan |first2=Ravi |last3=Tunkel |first3=David E. |last4=Sterni |first4=Laura M. |last5=Bober |first5=Michael B. |last6=Cho |first6=Tae-Joon |last7=Goldberg |first7=Michael J. |last8=Hoover-Fong |first8=Julie |last9=Irving |first9=Melita |last10=Kamps |first10=Shawn E. |last11=Mackenzie |first11=William G. |last12=Raggio |first12=Cathleen |last13=Spencer |first13=Samantha A. |last14=Bompadre |first14=Viviana |last15=White |first15=Klane K. |date=2021-12-01 |title=Best practice guidelines in managing the craniofacial aspects of skeletal dysplasia |journal=Orphanet Journal of Rare Diseases |language=en |volume=16 |issue=1 |page=31 |doi=10.1186/s13023-021-01678-8 |issn=1750-1172 |doi-access=free |pmid=33446226 |pmc=7809733}}</ref> pregnancy,<ref>{{cite journal |last1=Savarirayan |first1=Ravi |last2=Rossiter |first2=Judith P. |last3=Hoover-Fong |first3=Julie E. |last4=Irving |first4=Melita |last5=Bompadre |first5=Viviana |last6=Goldberg |first6=Michael J. |last7=Bober |first7=Michael B. |last8=Cho |first8=Tae-Joon |last9=Kamps |first9=Shawn E. |last10=Mackenzie |first10=William G. |last11=Raggio |first11=Cathleen |last12=Spencer |first12=Samantha S. |last13=White |first13=Klane K. |date=2018-12-01 |title=Best practice guidelines regarding prenatal evaluation and delivery of patients with skeletal dysplasia |journal=American Journal of Obstetrics and Gynecology |language=en |volume=219 |issue=6 |pages=545–562 |doi=10.1016/j.ajog.2018.07.017|pmid=30048634 |doi-access=free}}</ref> and peri-operative<ref>{{cite journal |last1=White |first1=Klane K. |last2=Bompadre |first2=Viviana |last3=Goldberg |first3=Michael J. |last4=Bober |first4=Michael B. |last5=Cho |first5=Tae-Joon |last6=Hoover-Fong |first6=Julie E. |last7=Irving |first7=Melita |last8=Mackenzie |first8=William G. |last9=Kamps |first9=Shawn E. |last10=Raggio |first10=Cathleen |last11=Redding |first11=Gregory J. |last12=Spencer |first12=Samantha S. |last13=Savarirayan |first13=Ravi |last14=Theroux |first14=Mary C. |last15=On behalf of the Skeletal Dysplasia Management Consortium |date=2017-10-01 |title=Best practices in peri-operative management of patients with skeletal dysplasias |url=https://onlinelibrary.wiley.com/doi/10.1002/ajmg.a.38357 |journal=American Journal of Medical Genetics Part A |language=en |volume=173 |issue=10 |pages=2584–2595 |doi=10.1002/ajmg.a.38357 |pmid=28763154 |hdl=11343/293252 |s2cid=22251966 |issn=1552-4825|hdl-access=free}}</ref> needs of people with achondroplasia.

Homozygous achondroplasia is invariably considered terminal even with aggressive treatment.

== Epidemiology ==
Achondroplasia is one of several congenital conditions with similar presentations, such as [[osteogenesis imperfecta]], [[multiple epiphyseal dysplasia]] tarda, [[achondrogenesis]], [[osteopetrosis]], and [[thanatophoric dysplasia]]. This makes estimates of prevalence difficult, with changing and subjective diagnostic criteria over time. One detailed and long-running study in the Netherlands found that the prevalence determined at birth was only 1.3 per 100,000 live births.<ref name=OMIM>{{OMIM|100800|ACHONDROPLASIA; ACH}}</ref> Another study at the same time found a rate of 1 per 10,000.<ref name=OMIM/> A 2020 review and meta-analysis estimated a worldwide prevalence of 4.6 per 100,000.<ref>{{cite journal|doi=10.1002/ajmg.a.61787|title=Birth prevalence of achondroplasia: A systematic literature review and meta-analysis|year=2020|last1=Foreman|first1=Pamela K.|last2=Kessel|first2=Femke|last3=Hoorn|first3=Rosa|last4=Bosch|first4=Judith|last5=Shediac|first5=Renée|last6=Landis|first6=Sarah|journal=American Journal of Medical Genetics Part A|volume=182|issue=10|pages=2297–2316|pmid=32803853|pmc=7540685}}</ref>

==Psychological and social aspects==
In addition to physical challenges, individuals with achondroplasia may also experience psychological challenges such as fear or negative perception of individuals with achondroplasia. Gollust et al. have indicated that adults with achondroplasia tend to have lower self-esteem, annual income, educational attainment, and overall quality of life (QOL) when compared to their unaffected siblings.<ref>{{cite journal |doi=10.1002/ajmg.a.20127 |title=Living with achondroplasia in an average-sized world: An assessment of quality of life |date=2003 |last1=Gollust |first1=Sarah E. |last2=Thompson |first2=Richard E. |last3=Gooding |first3=Holly C. |last4=Biesecker |first4=Barbara B. |journal=American Journal of Medical Genetics |volume=120A |issue=4 |pages=447–458 |pmid=12884421 |s2cid=38614817}}</ref> Interestingly, the Golust study revealed that the subjects were as likely to cite disadvantages relating to social barriers as those relating to health issues and functioning.{{citation needed|date=June 2024}}

On the other hand, other investigators, such as Ancona, state that for many individuals in immediate environments that have natural acceptance of the condition from the beginning, their main challenge lies in adapting to a world designed for those without the condition. However, when society rejects the condition from the start and associates it with destructive anxiety, it significantly damages the individual's self-image and leads to their social exclusion. Thus, the author hypothesizes, an accepting environment is crucial to prevent significant suffering for individuals with achondroplasia and to ensure the best outcomes for corrective interventions, rather than perpetuating rejection.<ref name =Ancona>{{cite book|doi=10.1007/978-1-4684-8712-1_56 |pmid=3240281 |chapter=The Psychodynamics of Achondroplasia |title=Human Achondroplasia |date=1988 |last1=Ancona |first1=Leonardo |series=Basic Life Sciences |volume=48 |pages=447–451 |isbn=978-1-4684-8714-5}}</ref>

Similarly, a study conducted in Japan by Nishimura and Hanaki found that children with achondroplasia faced challenges related to their short stature, but there was no indication of psychosocial maladjustment. They hypothesized that focusing on coping strategies and self-efficacy may play a crucial role in promoting psychological well-being among children with achondroplasia.<ref>{{cite journal | url=https://doi.org/10.1111/jocn.12531 | doi=10.1111/jocn.12531 | title=Psychosocial profiles of children with achondroplasia in terms of their short stature-related stress: A nationwide survey in Japan | date=2014 | last1=Nishimura | first1=Naoko | last2=Hanaki | first2=Keiichi | journal=Journal of Clinical Nursing | volume=23 | issue=21–22 | pages=3045–3056 | pmid=25453127}}</ref>

Social support and peer connections can be important for individuals with achondroplasia. Support groups, online communities, and advocacy organizations can provide a sense of belonging and can help individuals with achondroplasia connect with others who understand their experiences. Additionally, these communities can serve as a resource for information and support for both individuals with achondroplasia and their families. In the [[United States]], The Little People of America (LPA) is a national organization that provides support, resources, and advocacy for individuals with dwarfism, including achondroplasia.<ref name="LPA">Little People of America. (n.d.). About LPA. Retrieved from https://www.lpaonline.org/about-lpa</ref>

== Animals ==
[[Image:Munchkin cat grooming.jpg|thumb|left|Munchkin dwarf cat]]
Based on their disproportionate dwarfism, some dog breeds traditionally have been classified as "achondroplastic". This is the case for the [[dachshund]], [[basset hound]], [[Welsh Corgi|corgi]] and [[bulldog]] breeds.<ref>{{cite web|url=http://pets.webmd.com/dogs/features/pembroke-welsh-corgi-101|title=WebMD}}</ref><ref>{{cite book|author1=Jones, T.C.|author2=Hunt, R.D.|chapter=The musculoskeletal system|editor1=Jones, T.C.|editor2=Hunt, R.D.|editor3=Smith, H.A.|title=Veterinary Pathology|publisher=Lea & Febiger|location=Philadelphia|year=1979|isbn=978-0812107890|pages=1175–6|edition=5th}}</ref><ref>{{cite book|author=Willis M.B.|chapter=Inheritance of specific skeletal and structural defects|editor=Willis M.B.|title=Genetics of the Dog|publisher=Howell Book House|location=Great Britain|year=1989|isbn=978-0876055519|pages=[https://archive.org/details/geneticsofdog00will/page/119 119–120]|chapter-url-access=registration|chapter-url=https://archive.org/details/geneticsofdog00will|url=https://archive.org/details/geneticsofdog00will/page/119}}</ref> Data from whole genome association studies in short-limbed dogs reveal a strong association of this trait with a retro-gene coding for fibroblast growth factor 4 ([[FGF4]]).<ref>{{cite journal|vauthors=Parker HG, VonHoldt BM, Quignon P|title=An expressed fgf4 retrogene is associated with breed-defining chondrodysplasia in domestic dogs|journal=Science|volume=325|issue=5943|pages=995–8|date=August 2009|pmid=19608863|pmc=2748762|doi=10.1126/science.1173275|display-authors=etal|bibcode=2009Sci...325..995P}}</ref> Therefore, it seems unlikely that dogs and humans are achondroplastic for the same reasons. However, histological studies in some achondroplastic dog breeds have shown altered cell patterns in cartilage that are very similar to those observed in humans exhibiting achondroplasia.<ref>{{cite journal|vauthors=Braund KG, Ghosh P, Taylor TK, Larsen LH|title=Morphological studies of the canine intervertebral disc. The assignment of the beagle to the achondroplastic classification|journal=Res. Vet. Sci.|volume=19|issue=2|pages=167–72|date=September 1975|pmid=1166121|doi=10.1016/S0034-5288(18)33527-6}}</ref>

A similar form of achondroplasia was found in a litter of piglets from a phenotypically normal Danish sow. The dwarfism was inherited dominant in the offspring from this litter. The piglets were born phenotypically normal but became more and more symptomatic as they reached maturity.<ref>{{cite journal|vauthors=Nielsen VH, Bendixen C, Arnbjerg J|title=Abnormal growth plate function in pigs carrying a dominant mutation in type X collagen|journal=Mamm. Genome|volume=11|issue=12|pages=1087–92|date=December 2000|pmid=11130976|doi=10.1007/s003350010212|s2cid=2786778|display-authors=etal}}
</ref> This involved a mutation of the protein [[collagen, type X, alpha 1]], encoded by the COL10A1 gene.  In humans a similar mutation (G595E) has been associated with [[Schmid metaphyseal chondrodysplasia]] (SMCD), a relatively mild skeletal disorder that is also associated with dwarfism.{{citation needed|date=September 2021}}

The now extinct [[Ancon sheep]] was created by humans through the selective breeding of common domestic sheep with achondroplasia. The average-sized torso combined with the relatively smaller legs produced by achondroplasia was valued for making affected sheep less likely to escape without affecting the amount of wool or meat each sheep produced.<ref name="gidney">{{cite journal | last = Gidney | first = Louisa | title = Earliest Archaeological Evidence of the Ancon Mutation in Sheep from Leicester, UK | journal = International Journal of Osteoarchaeology | volume = 15 | issue = 27 | pages = 318–321 | date = May–June 1019 | doi = 10.1002/oa.872 | issn = 1099-1212}}</ref>

== See also ==
* [[List of radiographic findings associated with cutaneous conditions]]

== References ==
{{Reflist}}

== External links ==
{{Wiktionary}}
* {{cite book|author =Pauli RM|chapter=Achondroplasia|chapter-url=https://www.ncbi.nlm.nih.gov/books/NBK1152/|id=NBK1152|pmid=20301331|veditors=Pagon RA, Bird TD, Dolan CR|title=GeneReviews|publisher=University of Washington, Seattle|location=Seattle WA|year=1998|display-editors=etal}}

{{Medical resources
| oMIM_mult       = {{OMIM2|134934}}
| ICD10           = {{ICD10|Q|77|4|q|65}}
| ICD9            = {{ICD9|756.4}}
| DiseasesDB      = 80
| ICDO            =
| OMIM            = 100800
| MedlinePlus     = 001577
| eMedicineSubj   = article
| eMedicineTopic  = 1258401-overview
| MeshID          = D000130
| Orphanet        = 15
}}

{{Osteochondrodysplasia}}

{{Receptor deficiencies}}

[[Category:Cell surface receptor deficiencies]]
[[Category:Congenital disorders]]
[[Category:Connective tissue diseases]]
[[Category:Dwarfism]]
[[Category:Growth disorders]]
[[Category:Rare diseases]]
[[Category:Wikipedia medicine articles ready to translate]]