Editing Birth defect (section)

=== Primarily structural ===
Several terms are used to describe congenital abnormalities. (Some of these are also used to describe noncongenital conditions, and more than one term may apply in an individual condition.)

==== {{anchor|malformation|congenital malformation|malformation syndrome|congenital physical anomaly}}Terminology ====
* A '''congenital physical anomaly''' is an abnormality of the structure of a body part. It may or may not be perceived as a problem condition. Many, if not most, people have one or more [[minor physical anomalies]] if examined carefully. Examples of minor anomalies can include curvature of the fifth finger ([[clinodactyly]]), a third nipple, tiny indentations of the skin near the ears ([[Preauricular sinus and cyst|preauricular]] pits), shortness of the fourth [[metacarpal]] or [[metatarsal]] bones, or dimples over the lower spine ([[sacral dimple]]s). Some minor anomalies may be clues to more significant internal abnormalities.{{citation needed|date=December 2024}}
* '''Birth defect''' is a widely used term for a congenital malformation, ''i.e.'' a congenital, physical anomaly that is recognizable at [[Childbirth|birth]], and which is significant enough to be considered a problem. According to the [[Centers for Disease Control and Prevention]] (CDC), most birth defects are believed to be caused by a complex mix of factors including genetics, environment, and behaviors,<ref name="cdc">[https://www.cdc.gov/ncbddd/bd/research.htm Birth Defects Research] {{Webarchive|url=https://web.archive.org/web/20150924064625/http://www.cdc.gov/ncbddd/bd/research.htm |date=2015-09-24 }}. Centers for Disease Control and Prevention.</ref> though many birth defects have no known cause. An example of a birth defect is [[cleft palate]], which occurs during the fourth through seventh weeks of gestation.<ref name="cdc.gov">{{Cite web|url=https://www.cdc.gov/ncbddd/birthdefects/cleftlip.html|title=Facts about Cleft Lip and Cleft Palate {{!}} Birth Defects {{!}} NCBDDD {{!}} CDC|website=www.cdc.gov|access-date=2016-03-16|archive-date=2015-05-08|archive-url=https://web.archive.org/web/20150508162121/http://www.cdc.gov/ncbddd/birthdefects/CleftLip.html|url-status=live}}</ref> Body tissue and special cells from each side of the head grow toward the center of the face. They join to make the face.<ref name="cdc.gov" /> A cleft means a split or separation; the "roof" of the mouth is called the palate.<ref>{{Cite web|url=http://www.entnet.org/content/cleft-lip-and-cleft-palate|title=Cleft Lip and Cleft Palate|last=communications|website=American Academy of Otolaryngology–Head and Neck Surgery|access-date=2016-03-16|archive-date=2016-03-21|archive-url=https://web.archive.org/web/20160321210939/http://www.entnet.org/content/cleft-lip-and-cleft-palate|url-status=live}}</ref>
* A '''congenital malformation''' is a physical anomaly that is deleterious, ''i.e.'' a structural defect perceived as a problem. A typical combination of malformations affecting more than one body part is referred to as a '''malformation syndrome'''.{{citation needed|date=December 2024}}
* Some conditions are due to abnormal tissue development:
** A malformation is associated with a disorder of tissue development.<ref name="isbn0-7216-1489-2">{{cite book |author=Graham, John Whichello |title=Smith's Recognizable Patterns of Human Deformation, 3rd Edition |publisher=Saunders |location=Philadelphia |year=2007 |pages=3 |isbn=978-0-7216-1489-2 }}</ref> Malformations often occur in the first trimester.
** A [[dysplasia]] is a disorder at the organ level that is due to problems with tissue development.<ref name="isbn0-7216-1489-2" />
* Conditions also can arise after tissue is formed:
** A [[deformity|deformation]] is a condition arising from mechanical stress to normal tissue.<ref name="isbn0-7216-1489-2" /> Deformations often occur in the second or third trimester, and can be due to [[oligohydramnios]].{{citation needed|date=December 2024}}
** A disruption involves breakdown of normal tissues.<ref name="isbn0-7216-1489-2" />
* When multiple effects occur in a specified order, they are known as a [[sequence (medicine)|sequence]]. When the order is not known, it is a [[syndrome]].

==== Examples of primarily structural congenital disorders ====
A limb anomaly is called a [[dysmelia]]. These include all forms of limbs anomalies, such as [[amelia (birth defect)|amelia]], [[ectrodactyly]], [[phocomelia]], [[polymelia]], [[polydactyly]], [[syndactyly]], [[polysyndactyly]], [[oligodactyly]], [[brachydactyly]], [[dwarfism|achondroplasia]], congenital [[aplasia]] or [[hypoplasia]], [[amniotic band syndrome]], and [[cleidocranial dysostosis]].<ref>{{Cite journal |last1=Tayel |first1=SM |last2=Fawzia |first2=MM |last3=Al-Naqeeb |first3=Niran A |last4=Gouda |first4=Said |last5=Al Awadi |first5=SA |last6=Naguib |first6=KK |date=2005 |title=A morpho-etiological description of congenital limb anomalies |journal=Annals of Saudi Medicine |language=en |volume=25 |issue=3 |pages=219–227 |doi=10.5144/0256-4947.2005.219 |pmid=16119523 |pmc=6147980 |issn=0256-4947}}</ref>

[[Congenital heart defect]]s include [[patent ductus arteriosus]], [[atrial septal defect]], [[ventricular septal defect]], and [[tetralogy of Fallot]].

Congenital anomalies of the nervous system include neural tube defects such as [[spina bifida]], [[encephalocele]], and [[anencephaly]]. Other congenital anomalies of the nervous system include the [[Arnold–Chiari malformation]], the [[Dandy–Walker malformation]], [[hydrocephalus]], [[microencephaly]], [[megalencephaly]], [[lissencephaly]], [[polymicrogyria]], [[holoprosencephaly]], and [[agenesis of the corpus callosum]].<ref>{{Cite journal |last1=Gaitanis |first1=John |last2=Tarui |first2=Tomo |date=2018 |title=Nervous System Malformations |journal=CONTINUUM: Lifelong Learning in Neurology |language=en |volume=24 |issue=1 |pages=72–95 |doi=10.1212/CON.0000000000000561 |pmid=29432238 |pmc=6463295 |issn=1080-2371}}</ref>

Congenital anomalies of the [[gastrointestinal system]] include numerous forms of [[stenosis]] and [[atresia]], and perforation, such as [[gastroschisis]].<ref>{{Cite web |last=CDC |date=2021-03-31 |title=Congenital Anomalies of the Digestive System |url=https://www.cdc.gov/ncbddd/birthdefects/surveillancemanual/quick-reference-handbook/congenital-anomalies-of-digestive-system.html |access-date=2022-10-31 |website=Centers for Disease Control and Prevention |language=en-us |archive-date=2022-10-31 |archive-url=https://web.archive.org/web/20221031154232/https://www.cdc.gov/ncbddd/birthdefects/surveillancemanual/quick-reference-handbook/congenital-anomalies-of-digestive-system.html |url-status=live }}</ref>

Congenital anomalies of the kidney and urinary tract include renal parenchyma, kidneys, and urinary collecting system.<ref>{{cite web|title=Overview of congenital anomalies of the kidney and urinary tract (CAKUT)|url=http://www.uptodate.com/contents/overview-of-congenital-anomalies-of-the-kidney-and-urinary-tract-cakut|publisher=UpToDate – Wolters Kluer Health|access-date=29 October 2012|archive-date=27 June 2012|archive-url=https://web.archive.org/web/20120627062629/http://www.uptodate.com/contents/overview-of-congenital-anomalies-of-the-kidney-and-urinary-tract-cakut|url-status=live}}</ref>

Defects can be bilateral or unilateral, and different defects often coexist in an individual child.<ref>{{Cite journal |last1=Jain |first1=Sanjay |last2=Chen |first2=Feng |date=2018-12-01 |title=Developmental pathology of congenital kidney and urinary tract anomalies |journal=Clinical Kidney Journal |volume=12 |issue=3 |pages=382–399 |doi=10.1093/ckj/sfy112 |issn=2048-8505 |pmc=6543978 |pmid=31198539}}</ref>