Editing Microcephaly (section)

===Postnatal onset===
{{More citations needed section|date=February 2016}}
* Genetic
** Inborn errors of metabolism
**# [[Congenital disorder of glycosylation]]<ref>{{Cite web|url=https://rarediseases.org/rare-diseases/congenital-disorders-of-glycosylation/|title=Congenital Disorders of Glycosylation|website=NORD (National Organization for Rare Disorders)|access-date=2019-08-01}}</ref>
**# [[Mitochondrial disorders]]<ref>{{Cite web|url=https://www.mito.org.au/mito-info/|title=Mito Info|website=Mito Foundation|access-date=2019-08-01}}</ref>
**# [[Peroxisomal disorder]]<ref>{{Cite web|url=https://www.orpha.net/consor/cgi-bin/OC_Exp.php?Lng=GB&Expert=912|title=Zellweger syndrome|website=Orphanet|access-date=2019-08-01}}</ref>
**# [[Glucose transporter]] defect<ref>{{Cite web|url=https://ghr.nlm.nih.gov/condition/glut1-deficiency-syndrome|title=GLUT1 deficiency syndrome|last=Reference|first=Genetics Home|website=Genetics Home Reference|access-date=2019-08-01}}</ref>
**# [[Menkes disease]]
**# [[Congenital disorders of amino acid metabolism]]<ref>{{Cite web|url=https://www.orpha.net/consor/cgi-bin/OC_Exp.php?Expert=2209&lng=EN|title=Maternal phenylketonuria|website=Orphanet|access-date=2019-08-01}}</ref>
**# [[Organic acidemia]]<ref>{{Cite journal|last1=Reddy|first1=Nihaal|last2=Calloni|first2=Sonia F.|last3=Vernon|first3=Hilary J.|last4=Boltshauser|first4=Eugen|last5=Huisman|first5=Thierry A. G. M.|last6=Soares|first6=Bruno P.|date=2018-05-01|title=Neuroimaging Findings of Organic Acidemias and Aminoacidopathies|journal=RadioGraphics|volume=38|issue=3|pages=912–931|doi=10.1148/rg.2018170042|pmid=29757724|issn=0271-5333|doi-access=free}}</ref>
* Syndromes
** Contiguous gene deletion
**# 17p13.3 deletion ([[Miller–Dieker syndrome]])<ref>{{OMIM|247200|Miller-Dieker Lissencephaly Syndrome; MDLS}}</ref>
** Single gene defects
**# [[Rett syndrome]] (primarily girls)
**# [[Nijmegen breakage syndrome]]
**# X-linked [[lissencephaly]] with abnormal genitalia
**# [[Aicardi–Goutières syndrome]]
**# [[Ataxia telangiectasia]]
**# [[Cohen syndrome]]
**# [[Cockayne syndrome]]
* Acquired
** Disruptive injuries
**# [[Traumatic brain injury]]<ref>{{Citation|last1=Joyce|first1=Tina|title=Pediatric Abusive Head Trauma (Shaken Baby Syndrome)|date=2019|url=http://www.ncbi.nlm.nih.gov/books/NBK499836/|work=National Center for Biotechnology Information|publisher=AU.S. National Library of Medicine|pmid=29763011|access-date=2019-07-30|last2=Huecker|first2=Martin R.}}</ref>
**# [[Hypoxic-ischemic encephalopathy]]<ref name="Mayo Clinic" />
**# [[Ischemic stroke]]<ref name="UpToDate" />
**# [[Hemorrhagic stroke]]<ref name="UpToDate" />
** Infections
**# Congenital [[HIV encephalopathy]]<ref>{{Cite journal|last1=Donald|first1=Kirsten A.|last2=Walker|first2=Kathleen G.|last3=Kilborn|first3=Tracy|last4=Carrara|first4=Henri|last5=Langerak|first5=Nelleke G|last6=Eley|first6=Brian|last7=Wilmshurst|first7=Jo M|date=2015|title=HIV Encephalopathy: pediatric case series description and insights from the clinic coalface|journal=AIDS Research and Therapy|volume=12|issue=1|page=2|doi=10.1186/s12981-014-0042-7|issn=1742-6405|pmc=4297380|pmid=25598835 |doi-access=free }}</ref>
**# [[Meningitis]]<ref>{{Cite journal|last1=Tibussek|first1=Daniel|last2=Sinclair|first2=Adriane|last3=Yau|first3=Ivanna|last4=Teatero|first4=Sarah|last5=Fittipaldi|first5=Nahuel|last6=Richardson|first6=Susan E.|last7=Mayatepek|first7=Ertan|last8=Jahn|first8=Peter|last9=Askalan|first9=Rand|date=2015|title=Late-Onset Group B Streptococcal Meningitis Has Cerebrovascular Complications|journal=The Journal of Pediatrics|volume=166|issue=5|pages=1187–92.e1|doi=10.1016/j.jpeds.2015.02.014|pmid=25919727}}</ref>
**# [[Encephalitis]]<ref>{{Cite journal|last1=Ramos|first1=Regina|last2=Viana|first2=Rafaela|last3=Brainer-Lima|first3=Alessandra|last4=Florêncio|first4=Telma|last5=Carvalho|first5=Maria Durce|last6=van Der Linden|first6=Vanessa|last7=Amorim|first7=Antonio|last8=Rocha|first8=Maria Ângela|last9=Medeiros|first9=Fabíola|date=2017|title=Perinatal Chikungunya Virus-Associated Encephalitis Leading to Postnatal-Onset Microcephaly and Optic Atrophy|journal=The Pediatric Infectious Disease Journal|volume=37|issue=1|pages=94–95|doi=10.1097/INF.0000000000001690|pmid=28737626|s2cid=31790738|issn=0891-3668}}</ref>
** Toxins
*** [[Chronic kidney failure]]<ref>{{Cite web|url=https://rarediseases.org/rare-diseases/galloway-mowat-syndrome/|title=Galloway-Mowat Syndrome|website=NORD (National Organization for Rare Disorders)|access-date=2019-08-02|archive-date=2021-03-11|archive-url=https://web.archive.org/web/20210311133130/https://rarediseases.org/rare-diseases/galloway-mowat-syndrome/|url-status=dead}}</ref>
** Deprivation
**# [[Hypothyroidism]]<ref>{{Cite journal|last1=Kurian|first1=Manju A|last2=Jungbluth|first2=Heinz|date=July 2014|title=Genetic disorders of thyroid metabolism and brain development|journal=Developmental Medicine and Child Neurology|volume=56|issue=7|pages=627–634|doi=10.1111/dmcn.12445|issn=0012-1622|pmc=4231219|pmid=24665922}}</ref>
**# [[Anemia]]<ref>{{Cite web|url=https://ghr.nlm.nih.gov/condition/fanconi-anemia|title=Fanconi anemia|last=Reference|first=Genetics Home|website=Genetics Home Reference|access-date=2019-08-02}}</ref>
**# [[Congenital heart disease]]<ref>{{Cite journal|last1=Damlich|first1=Jennifer|last2=Qato|first2=Roa|last3=Cruz|first3=Meredith|last4=Colon|first4=Maria|last5=Wilkins|first5=Isabelle|date=2009-07-01|title=Discussion: 'Microcephaly associated with congenital heart defect' by Barbu et al|url=https://www.ajog.org/article/S0002-9378(09)00556-0/abstract|journal=American Journal of Obstetrics & Gynecology|language=en|volume=201|issue=1|pages=e7–e12|doi=10.1016/j.ajog.2009.05.042|pmid=19576365|issn=0002-9378|doi-access=free}}</ref>
**# [[Malnutrition]]<ref>{{Cite web|url=https://www.cdc.gov/ncbddd/birthdefects/microcephaly.html|title=Facts about Microcephaly |date=2016-12-07|publisher=Centers for Disease Control and Prevention|access-date=2019-08-02}}</ref>

Genetic mutations cause most cases of microcephaly.<ref name="NIH2015" /> Relationships have been found between [[autism]], duplications of genes and [[macrocephaly]] on one side. On the other side, a relationship has been found between [[schizophrenia]], deletions of genes and microcephaly.<ref>{{cite journal |author1-link=Bernard Crespi|last1=Crespi |first1=B. |last2=Stead |first2=P. |last3=Elliot |first3=M. |title=Evolution in health and medicine Sackler colloquium: Comparative genomics of autism and schizophrenia |journal=  Proceedings of the National Academy of Sciences of the United States of America|volume=107 |issue=Suppl 1 |pages=1736–41 |date=January 2010 |pmid=19955444 |pmc=2868282 |doi=10.1073/pnas.0906080106 |bibcode=2010PNAS..107.1736C |doi-access=free }}</ref><ref>{{cite journal |title=Rare chromosomal deletions and duplications increase risk of schizophrenia |journal=Nature |volume=455 |issue=7210 |pages=237–241 |date=September 2008 |pmid=18668038 |doi=10.1038/nature07239 |bibcode = 2008Natur.455..237S |last1=Stone |first1=Jennifer L. |last2=O'Donovan |first2=Michael C. |last3=Gurling |first3=Hugh |last4=Kirov |first4=George K. |last5=Blackwood |first5=Douglas H. R. |last6=Corvin |first6=Aiden |last7=Craddock |first7=Nick J. |last8=Gill |first8=Michael |last9=Hultman |first9=Christina M. |last10=Lichtenstein |first10=Paul |last11=McQuillin |first11=Andrew |last12=Pato |first12=Carlos N. |last13=Ruderfer |first13=Douglas M. |last14=Owen |first14=Michael J. |last15=St Clair |first15=David |last16=Sullivan |first16=Patrick F. |last17=Sklar |first17=Pamela |last18=Purcell (Leader) |first18=Shaun M. |last19=Stone |first19=Jennifer L. |last20=Ruderfer |first20=Douglas M. |last21=Korn |first21=Joshua |last22=Kirov |first22=George K. |last23=MacGregor |first23=Stuart |last24=McQuillin |first24=Andrew |last25=Morris |first25=Derek W. |last26=O'Dushlaine |first26=Colm T. |last27=Daly |first27=Mark J. |last28=Visscher |first28=Peter M. |last29=Holmans |first29=Peter A. |last30=o'Donovan |first30=Michael C. |display-authors=6 |pmc=3912847}}</ref><ref>{{cite journal |vauthors=Dumas L, Sikela JM |title=DUF1220 domains, cognitive disease, and human brain evolution |journal=Cold Spring Harb. Symp. Quant. Biol. |volume=74 |pages=375–382 |year=2009 |pmid=19850849 |pmc=2902282 |doi=10.1101/sqb.2009.74.025 }}</ref> Several genes have been designated "MCPH" genes, after [[microcephalin]] (''MCPH1''), based on their role in brain size and primary microcephaly syndromes when mutated. In addition to microcephalin, these include ''[[WDR62]]'' (''MCPH2''), ''[[CDK5RAP2]]'' (''MCPH3''), ''[[KNL1]]'' (''MCPH4''), [[ASPM (gene)|''ASPM'']] (''MCPH5''), ''[[CENPJ]]'' (''MCPH6''), ''[[STIL]]'' (''MCPH7''), ''[[CEP135]]'' (''MCPH8''), ''[[CEP152]]'' (''MCPH9''), ''[[ZNF335]]'' (''MCPH10''), ''[[PHC1]]'' (''MCPH11'') and ''[[CDK6]]'' (''MCPH12'').<ref name="BMC" /> Moreover, an association has been established between common genetic variants within known microcephaly genes (such as ''MCPH1'' and ''CDK5RAP2'') and normal variation in brain structure as measured with [[magnetic resonance imaging]] (MRI){{nsmdns}}i.e., primarily brain [[Cerebral cortex|cortical]] surface area and total brain volume.<ref name="Rimol_2010">{{cite journal |bibcode=2010PNAS..107..384R |jstor=40536283 |title=Sex-dependent association of common variants of microcephaly genes with brain structure |last1=Rimol |first1=Lars M. |last2=Agartz |first2=Ingrid |last3=Djurovic |first3=Srdjan |last4=Brown |first4=Andrew A. |last5=Roddey |first5=J. Cooper |last6=Kahler |first6=Anna K. |last7=Mattingsdal |first7=Morten |last8=Athanasiu |first8=Lavinia |last9=Joyner |first9=Alexander H. |last10=Schork |first10=N. J. |last11=Halgren |first11=E. |last12=Sundet |first12=K. |last13=Melle |first13=I. |last14=Dale |first14=A. M. |last15=Andreassen |first15=O. A. |last16=Weiner |first16=M. |last17=Thal |first17=L. |last18=Petersen |first18=R. |last19=Jack |first19=C. R. |last20=Jagust |first20=W. |last21=Trojanowki |first21=J. |last22=Toga |first22=A. W. |last23=Beckett |first23=L. |last24=Green |first24=R. C. |last25=Gamst |first25=A. |last26=Potter |first26=W. Z. |last27=Montine |first27=T. |last28=Anders |first28=D. |last29=Bernstein |first29=M. |last30=Felmlee |first30=J. |volume=107 |year=2010 |pages=384–8 |journal=Proceedings of the National Academy of Sciences |doi=10.1073/pnas.0908454107 |pmid=20080800 |issue=1 |pmc=2806758|display-authors=6 |doi-access=free }}</ref>