Editing Dwarfism (section)

==Causes==
[[File:Seneb and wife statue.jpg|upright|thumb|[[Seneb]], court official and priest for the [[Ancient Egypt]]ian rulers [[Khufu]] and [[Djedefre]], with his wife Senetites and their children<ref>''Ancient Egypt: Kingdom of the Pharaohs'', R. Hamilton, p. 47, Paragon, 2006, {{ISBN|1-4054-8288-5}}</ref>]]
Dwarfism can result from many medical conditions, each with its own separate symptoms and causes. Extreme shortness in humans with proportional body parts usually has a hormonal cause, such as [[growth hormone deficiency]], once called ''pituitary dwarfism''.<ref name="LPA"/><ref name="dwarfism-pbshome">{{cite web |url=https://www.pbs.org/pov/pov2005/bigenough/special_dwarfism_ety.html |title=Big Enough. What is Dwarfism? |date=2006-08-08 |last=Kennedy |first=Dan |website=[[POV (TV series)]] |publisher=[[PBS]] (Public Broadcasting Service) |access-date=2008-11-18 |archive-date=2009-03-13 |archive-url=https://web.archive.org/web/20090313112314/http://www.pbs.org/pov/pov2005/bigenough/special_dwarfism_ety.html |url-status=dead}}</ref> Achondroplasia is responsible for the majority of human dwarfism cases, followed by [[spondyloepiphyseal dysplasia]] and [[diastrophic dysplasia]].<ref name="urlDwarfism">{{cite web|url=http://kidshealth.org/parent/growth/growth/dwarfism.html|title=Dwarfism|publisher=[[KidsHealth]]|access-date=2015-06-30}}</ref>

===Achondroplasia===
{{further|Achondroplasia}}
The most recognizable and most common form of dwarfism in humans is achondroplasia, which accounts for 70% of dwarfism cases, and occurs in 4 to 15 out of 100,000 live births.<ref name="Çevik-2010">{{Cite journal|last1=Çevik|first1=Banu|last2=Çolakoğlu|first2=Serhan|url=http://www.meja.aub.edu.lb/downloads/20_6/907.pdf|title=Anesthetic management of achondroplastic dwarf undergoing cesarean section|journal=M.E.J. Anesth.|volume=20|issue=6|year=2010|archive-url=https://web.archive.org/web/20180713022612/http://www.meja.aub.edu.lb/downloads/20_6/907.pdf|url-status=dead|archive-date=July 13, 2018}}</ref>

It produces [[Rhizomelia|rhizomelic]] short limbs, increased spinal curvature, and distortion of skull growth. In achondroplasia the body's limbs are proportionately shorter than the trunk (abdominal area), with a larger head than average and characteristic facial features. Achondroplasia is an [[autosomal dominant]] disorder caused by the presence of an altered [[allele]] in the genome. If a pair of achondroplasia alleles are present, the result is fatal, usually perinatally. Achondroplasia is a mutation in the [[fibroblast growth factor receptor 3]].<ref>{{Gene|FGFR3}}</ref> In the context of achondroplasia, this mutation causes FGFR3 to become constitutively active, inhibiting bone growth.<ref>{{cite web |url=http://ghr.nlm.nih.gov/condition=achondroplasia |title=Achondroplasia – Genetics Home Reference |date=2008-09-26|work=Genetics Home Reference|publisher=National Institute of Health |access-date=2008-10-01}}</ref>

===Growth hormone deficiency===
{{further|Growth hormone deficiency}}
Growth hormone deficiency (GHD) is a medical condition in which the body produces insufficient [[growth hormone]]. Growth hormone, also called somatotropin, is a [[polypeptide]] [[hormone]] which stimulates [[Human development (biology)|growth]] and cell reproduction. If this hormone is lacking, stunted or even halted growth may become apparent. Children with this disorder may grow slowly and puberty may be delayed by several years or indefinitely. Growth hormone deficiency has no single definite cause. It can be caused by mutations of specific genes, damage to the pituitary gland, [[Turner's syndrome]], poor nutrition,<ref name="ghdeficiency">{{cite web | publisher = UK Child Growth Foundation | title = Growth Hormone Deficiency | url = http://www.childgrowthfoundation.org/ghd.htm | access-date = 2009-01-16 | archive-url = https://web.archive.org/web/20090116030454/http://www.childgrowthfoundation.org/ghd.htm | archive-date = 2009-01-16 | url-status = dead }}</ref> or even stress (leading to [[psychogenic dwarfism]]). [[Laron syndrome]] (growth hormone insensitivity) is another cause. Those with growth hormone issues tend to be proportionate.

===Metatropic dysplasia===
Metatropic means "changing form" and refers to this form of skeletal dysplasia as there is an abnormality in the growth plates.<ref>{{cite web |url=https://www.hopkinsmedicine.org/health/conditions-and-diseases/metatropic-dysplasia#:~:text=What%20is%20metatropic%20dysplasia%3F,flattening%20of%20the%20vertebral%20bodies |title=Metatropic Dysplasia &#124; |publisher=Johns Hopkins Medicine |date=2022-02-03 |access-date=2022-03-02}}</ref> Skeletal changes continue over time and may need surgical intervention to help protect the lungs.<ref name="NIH Rared Dseases">{{cite web|url=https://rarediseases.info.nih.gov/diseases/3571/metatropic-dysplasia |title=Metatropic dysplasia &#124; Genetic and Rare Diseases Information Center (GARD) – an NCATS Program |website=Rarediseases.info.nih.gov |date= |access-date=2022-03-02}}</ref> Symptoms starting at birth may be mild or can be fatal.<ref name="Medlineplus.gov">{{Cite web|url=https://medlineplus.gov/genetics/condition/metatropic-dysplasia/|title=Metatropic dysplasia: MedlinePlus Genetics|website=Medlineplus.gov|access-date=2 March 2022}}</ref> There are recognizable features in individuals with this genetic disorder. Some are short stature, narrow chest, "facial features such as a prominent forehead, underdevelopment of the upper jaw, cheekbones and eye sockets (midface hypoplasia), and a squared-off jaw."<ref name="NIH Rared Dseases"/> It is considered a more severe skeletal dysplasia, but is very rare, with the exact number of those affected unknown.<ref name="Medlineplus.gov"/> Prognosis is largely on a case-by-case basis depending on the severity, and life expectancy may not be impacted unless there are respiratory complications.<ref>{{cite web|url=https://www.orpha.net/consor/cgi-bin/OC_Exp.php?lng=en&Expert=2635 |title=Orphanet: Metatropic dysplasia |website=Orpha.net |date=2017-05-17 |access-date=2022-03-02}}</ref>

===Other===
[[File:Sehaj sekhon.jpg|thumb|199x199px|Sehaj Sekhon, an Indian man with dwarfism caused by [[NPR2]] disproportionate dwarfism.]]
Other causes of dwarfism are [[spondyloepiphyseal dysplasia congenita]], [[diastrophic dysplasia]], [[pseudoachondroplasia]], [[hypochondroplasia]], [[Noonan syndrome]], [[primordial dwarfism]], [[Cockayne syndrome]], [[Kniest dysplasia]], [[Turner syndrome]], [[osteogenesis imperfecta]] (OI), and [[hypothyroidism]]. Severe shortness with skeletal distortion also occurs in several of the [[Mucopolysaccharidosis|mucopolysaccharidoses]] and other [[lysosomal storage disease|storage disorders]].<ref>{{cite web |url=http://www.wrongdiagnosis.com/d/dwarfism/causes.htm |title=Causes of Dwarfism |website=WrongDiagnosis.com |access-date=2009-03-23}}</ref> [[Hypogonadotropic hypogonadism]] may cause proportionate, yet temporary, dwarfism. [[NPR2]] disproportionate dwarfism was discovered recently and is caused by a mutant gene.<ref>{{cite web|title=A Loss-of-Function Mutation in Natriuretic Peptide Receptor 2 (Npr2) Gene Is Responsible for Disproportionate Dwarfism in cn/cn Mouse|url=https://www.jbc.org/article/S0021-9258(19)60512-0/pdf|format=PDF|website=Jbc.org}}</ref>