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| {{more citations needed|date=September 2013}}
| | '''Schizencephaly''' is a rare [[birth defect]] 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. |
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| | name = Schizencephaly
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| | image = Schizenzephalie CT axial.jpg
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| | caption = Axial CT scan showing schizencephaly in a 6-year-old child
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| '''Schizencephaly''' ({{etymology|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]] 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|accessdate=4 November 2014}}</ref> | |
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| ==Presentation== | | ==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|accessdate=2013-09-11}}</ref> | | 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 bilateral clefts often exhibit developmental delays, speech and [[language]] difficulties, and [[corticospinal]] dysfunction. Unilateral clefts may result in weakness or paralysis on one side of the body with potentially average or near-average intelligence. Other features include: |
| | * [[Microcephaly]] |
| | * [[Cognitive impairment]] |
| | * [[Hemiparesis]] or [[quadriparesis]] |
| | * [[Hypotonia]] |
| | * [[Seizures]] |
| | * [[Hydrocephalus]] |
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| ==Causes== | | ==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, but likely the cause may be either genetic or a physical insult, such as infection, infarction, hemorrhage, in utero stroke, exposure to a toxin, or mutation. It is thought that normal neuron migration during the second trimester of intrauterine development, 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.
| | Schizencephaly is thought to result from early disruption of grey matter migration during embryogenesis. The underlying causes may include genetic mutations or environmental insults such as infections, infarctions, hemorrhages, in utero strokes, or exposure to toxins. Normal neuron migration during the second trimester of development is disrupted, leading to the malformation. |
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| ===Genetic=== | | ===Genetic=== |
| 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}}</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}}</ref><ref>{{Cite journal|last=Smigiel|first=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>
| | Some cases have been linked to mutations in genes such as ''[[COL4A1]]'', which play a role in brain development and structural integrity. |
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| ===In utero infections=== | | ===In utero infections=== |
| Causes of schizencephaly may also be caused by environmental exposures during pregnancy sickness during pregnancy (such as [[Cytomegalovirus]]), exposure to [[toxin]]s, or a vascular insult. Often there are additional associated heterotopias (isolated islands of neurons) which indicate a failure of migration of the neurons to their final position in the brain caused by possible stroke.
| | Environmental exposures during pregnancy, such as maternal infections like [[Cytomegalovirus]], toxin exposure, or vascular events, can also contribute to the condition. Associated heterotopias (misplaced neurons) are often observed, indicating disrupted neuronal migration. |
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| ==Diagnosis== | | ==Diagnosis== |
| * Radiological methods like [[computed tomography]] (CT) and/or [[magnetic resonance imaging]] (MRI) - unilateral or bilateral clefting of the brain. | | Diagnosis is typically made using imaging studies, such as: |
| * Genetic testing for confirmation of mutations in the genes associated with susceptibility to the condition.
| | * [[Computed tomography]] (CT) |
| | * [[Magnetic resonance imaging]] (MRI) |
| | Genetic testing may confirm mutations associated with susceptibility to the condition. |
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| ==Treatment== | | ==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.
| | Management focuses on addressing symptoms and may include: |
| | * Physical therapy using neurodevelopmental techniques |
| | * Occupational therapy with specific emphasis on neurological approaches |
| | * Seizure management |
| | * Placement of a shunt in cases of hydrocephalus |
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| ==Prognosis== | | ==Prognosis== |
| The prognosis for individuals with schizencephaly varies depending on the size of the clefts and the degree of neurological deficit.<ref name=ninds /> | | The prognosis for schizencephaly varies based on the size of the clefts and the degree of neurological impairment. Individuals with smaller or unilateral clefts generally have better outcomes compared to those with bilateral clefts. |
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| ==Frequency == | | ==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|accessdate=4 November 2014}}</ref>
| | Although schizencephaly is rare, having a sibling with the condition increases the risk, suggesting a potential genetic component. Certain gene mutations, including those in [[SIX3]] and ''[[COL4A1]]'', may be implicated. |
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| ==References==
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| == External links == | | == External links == |
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| | Orphanet=799 | | | Orphanet=799 |
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| *{{NINDS|Schizencephaly}}
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| * [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] | | * [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] |
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Schizencephaly is a rare birth defect 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.
Presentation
Schizencephaly can be distinguished from porencephaly by the fact that in schizencephaly, the fluid-filled component is entirely lined by heterotopic grey matter, while a porencephalic cyst is lined mostly by white matter. Individuals with bilateral clefts often exhibit developmental delays, speech and language difficulties, and corticospinal dysfunction. Unilateral clefts may result in weakness or paralysis on one side of the body with potentially average or near-average intelligence. Other features include:
Causes
Schizencephaly is thought to result from early disruption of grey matter migration during embryogenesis. The underlying causes may include genetic mutations or environmental insults such as infections, infarctions, hemorrhages, in utero strokes, or exposure to toxins. Normal neuron migration during the second trimester of development is disrupted, leading to the malformation.
Genetic
Some cases have been linked to mutations in genes such as COL4A1, which play a role in brain development and structural integrity.
In utero infections
Environmental exposures during pregnancy, such as maternal infections like Cytomegalovirus, toxin exposure, or vascular events, can also contribute to the condition. Associated heterotopias (misplaced neurons) are often observed, indicating disrupted neuronal migration.
Diagnosis
Diagnosis is typically made using imaging studies, such as:
Genetic testing may confirm mutations associated with susceptibility to the condition.
Treatment
Management focuses on addressing symptoms and may include:
- Physical therapy using neurodevelopmental techniques
- Occupational therapy with specific emphasis on neurological approaches
- Seizure management
- Placement of a shunt in cases of hydrocephalus
Prognosis
The prognosis for schizencephaly varies based on the size of the clefts and the degree of neurological impairment. Individuals with smaller or unilateral clefts generally have better outcomes compared to those with bilateral clefts.
Frequency
Although schizencephaly is rare, having a sibling with the condition increases the risk, suggesting a potential genetic component. Certain gene mutations, including those in SIX3 and COL4A1, may be implicated.
External links
