View source for Schizencephaly

{{short description|Brain malformation; large clefts in the cerebrum}}
{{more citations needed|date=September 2013}}
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| name            = Schizencephaly
| image           = Schizenzephalie CT axial.jpg
| caption         = Axial CT scan showing schizencephaly in a 6-year-old child
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'''Schizencephaly''' ({{ety|gre|skhizein|to split||enkephalos|brain}})<ref>{{cite encyclopedia|title=schizo–|encyclopedia=The New Oxford American Dictionary|edition=2nd}}</ref><ref>{{cite encyclopedia|title=encephalic|encyclopedia=The New Oxford American Dictionary|edition=2nd}}</ref> is a rare [[birth defect]] of the [[Human brain|brain]], characterized by abnormal clefts lined with [[grey matter]] that form the [[ependyma]] of the [[cerebral ventricles]] to the [[pia mater]]. These clefts can occur bilaterally or unilaterally. Common clinical features of this malformation include [[epilepsy]], motor deficits, and [[psychomotor retardation]].<ref name=Schiz>{{cite web|title=Schizencephaly|url=http://www.orpha.net/consor/cgi-bin/OC_Exp.php?Lng=GB&Expert=799|website=Orphanet|access-date=4 November 2014}}</ref>

==Presentation==
Schizencephaly can be distinguished from [[porencephaly]] by the fact that in schizencephaly, the fluid-filled component is entirely lined by [[Heterotopia (medicine)|heterotopic]] grey matter, while a porencephalic cyst is lined mostly by [[white matter]]. Individuals with clefts in both hemispheres, or bilateral clefts, are often developmentally delayed and have delayed speech and [[language]] skills and [[corticospinal]] dysfunction. Individuals with smaller, unilateral clefts (clefts in one hemisphere) may be weak or paralyzed on one side of the body and may have average or near-average intelligence. Patients with schizencephaly may also have varying degrees of [[microcephaly]], [[Cognitive impairment]], [[hemiparesis]] (weakness or paralysis affecting one side of the body), or [[quadriparesis]] (weakness or paralysis affecting all four extremities), and may have reduced muscle tone (hypotonia). Most patients have seizures, and some may have [[hydrocephalus]].<ref name=ninds>{{cite web|url=http://www.ninds.nih.gov/disorders/Schizencephaly/schizencephaly.htm|title=NINDS Schizencephaly Information Page|work=National Institute of Neurological Disorders and Stroke|publisher=NIH|access-date=2013-09-11|archive-date=2013-09-11|archive-url=https://web.archive.org/web/20130911124625/http://www.ninds.nih.gov/disorders/Schizencephaly/schizencephaly.htm|url-status=dead}}</ref>

==Causes==
In schizencephaly, the neurons border the edge of the cleft, implying a very early disruption of the usual grey matter migration during embryogenesis. The cause of the disruption is not known; however it is likely the cause may be either a [[Mutation|genetic mutation]] or a physical insult, such as an infection, an [[infarction]], [[hemorrhaging]], a [[stroke]] while in utero, or exposure to a toxin. Schizencephaly may also be caused by infection during pregnancy, such as [[Cytomegalovirus]]. 

It is thought that normal neuron migration, during the second trimester of intrauterine development, is when primitive neuron precursors (germinal matrix) migrate from just beneath the ventricular ependyma to the peripheral hemispheres [[Collagen, type IV, alpha 1|where]] they form the cortical grey matter. Often, with schizencephaly, there are additional associated [[Heterotopia (medicine)|heterotopias]] (isolated islands of neurons) which indicate a failure of migration of the neurons to their final position in the brain, possibly caused by a stroke. {{cn|date=February 2021}}{{what|date=February 2021}}

===Genetic cause===
There was once thought to be a genetic association with the ''[[EMX2]]'' gene, although this theory has recently lost support.<ref>{{cite journal|last1=Tietjen|first1=Ian|last2=Bodell|first2=Adria|last3=Apse|first3=Kira|last4=Mendonza|first4=Ashley M.|last5=Chang|first5=Bernard S.|last6=Shaw|first6=Gary M.|last7=Barkovich|first7=A. James|last8=Lammer|first8=Edward J.|last9=Walsh|first9=Christopher A.|title=Comprehensive EMX2 genotyping of a large schizencephaly case series.|journal=American Journal of Medical Genetics Part A|date=15 June 2007|volume=143A|issue=12|pages=1313–1316|doi=10.1002/ajmg.a.31767|pmid=17506092|s2cid=34724677}}</ref> However it has been confirmed that mutations in the ''[[Collagen, type IV, alpha 1|COL4A1]]'' gene occur in some patients with schizencephaly.<ref>{{cite journal|last1=Yoneda|first1=Yuriko|last2=Haginoya|first2=Kazuhiro|last3=Kato|first3=Mitsuhiro|last4=Osaka|first4=Hitoshi|last5=Yokochi|first5=Kenji|last6=Arai|first6=Hiroshi|last7=Kakita|first7=Akiyoshi|last8=Yamamoto|first8=Takamichi|last9=Otsuki|first9=Yoshiro|last10=Shimizu|first10=Shin-ichi|last11=Wada|first11=Takahito|last12=Koyama|first12=Norihisa|last13=Mino|first13=Yoichi|last14=Kondo|first14=Noriko|last15=Takahashi|first15=Satoru|last16=Hirabayashi|first16=Shinichi|last17=Takanashi|first17=Jun-ichi|last18=Okumura|first18=Akihisa|last19=Kumagai|first19=Toshiyuki|last20=Hirai|first20=Satori|last21=Nabetani|first21=Makoto|last22=Saitoh|first22=Shinji|last23=Hattori|first23=Ayako|last24=Yamasaki|first24=Mami|last25=Kumakura|first25=Akira|last26=Sugo|first26=Yoshinobu|last27=Nishiyama|first27=Kiyomi|last28=Miyatake|first28=Satoko|last29=Tsurusaki|first29=Yoshinori|last30=Doi|first30=Hiroshi|last31=Miyake|first31=Noriko|last32=Matsumoto|first32=Naomichi|last33=Saitsu|first33=Hirotomo|title=Phenotypic Spectrum of Mutations: Porencephaly to Schizencephaly|journal=Annals of Neurology|date=January 2013|volume=73|issue=1|pages=48–57|doi=10.1002/ana.23736|pmid=23225343|s2cid=3218598}}</ref><ref>{{Cite journal|last1=Smigiel|first1=Robert|last2=Cabala|first2=Magdalena|last3=Jakubiak|first3=Aleksandra|last4=Kodera|first4=Hirofumi|last5=Sasiadek|first5=Marek J.|last6=Matsumoto|first6=Naomichi|last7=Sasiadek|first7=Maria M.|last8=Saitsu|first8=Hirotomo|date=2016-04-01|title=Novel COL4A1 mutation in an infant with severe dysmorphic syndrome with schizencephaly, periventricular calcifications, and cataract resembling congenital infection|journal=Birth Defects Research Part A: Clinical and Molecular Teratology|language=en|volume=106|issue=4|pages=304–307|doi=10.1002/bdra.23488|issn=1542-0760|pmid=26879631}}</ref>

==Diagnosis==
* Radiological methods like [[computed tomography]] (CT) and/or [[magnetic resonance imaging]] (MRI) - unilateral or bilateral clefting of the brain.
* [[Genetic testing]] for confirmation of mutations in the genes associated with susceptibility to the condition.

==Treatment==
Treatment for individuals with schizencephaly generally consists of physical therapy (KG-ZNS with Vojta Methode), occupational therapy (with specific emphasis on neuro-developmental therapy techniques), treatment for seizures,<ref name=ninds /> and, in cases that are complicated by [[hydrocephalus]], a shunt.

==Prognosis==
The prognosis for individuals with schizencephaly varies depending on the size of the clefts and the degree of neurological deficit.<ref name=ninds />

==Frequency==
In some cases, the defect is linked to mutations of the [[EMX2]], [[SIX3]], and [[Collagen, type IV, alpha 1]] genes. Because having a sibling with schizencephaly has been statistically shown to increase risk of the disorder, it is possible that there is a heritable genetic component to the disease.<ref>{{cite web|last1=Skandhan|first1=Avni|last2=Gaillard|first2=Frank|title=Schizencephaly|url=http://radiopaedia.org/articles/schizencephaly|website=Radiopedia|access-date=4 November 2014}}</ref>

==References==
{{reflist}}
9.^ Herrera Ortiz, A., & Ortiz Sandoval, H. (2021). Open Lip Schizencephaly: A Case Report. Revista Cuarzo, 26(2), 27-29.        https://doi.org/10.26752/cuarzo.v26.n2.510

== External links ==
* {{NINDS|Schizencephaly}}
* [http://www.omim.org/search?index=entry&start=1&limit=10&sort=score+desc&search=number:(269160+OR+603714) OMIM entries on Familial Schizencephaly, SIX3-Related]
{{Medical resources
| ICD11           = {{ICD11|LA05.61}}
|   ICD10          = {{ICD10|Q|04|6|q|00}}
|   ICD9           = {{ICD9|742.4}}
|   ICDO           =
|   OMIM           = 269160
|   OMIM_mult      =
|   MedlinePlus    =
|   eMedicineSubj  = radio
|   eMedicineTopic = 622
|   DiseasesDB     = 33031
|   MeshID         = D054220
| Orphanet=799
}}

{{Congenital malformations and deformations of nervous system}}

[[Category:Congenital disorders of nervous system]]
[[Category:Rare diseases]]