Editing Macrocephaly (section)

==Causes==
[[File:Macrocephalic idiot.jpg|thumb|Normocephaly (left) vs. macrocephaly (right))]]
Many people with abnormally large heads or large skulls are healthy, but macrocephaly may be pathological. Pathologic macrocephaly may be due to [[megalencephaly]] (enlarged brain), [[hydrocephalus]] (abnormally increased [[cerebrospinal fluid]]), cranial [[hyperostosis]] (bone overgrowth), and other conditions. Pathologic macrocephaly is called "syndromic", when it is associated with any other noteworthy condition, and "nonsyndromic" otherwise. Pathologic macrocephaly may be caused by [[congenital]] anatomic abnormalities, genetic conditions, or by environmental events.<ref name=Williams/>

Many genetic conditions are associated with macrocephaly, including familial macrocephaly related to the holgate gene, [[autism]], [[PTEN (gene)|''PTEN'']] mutations such as [[Cowden disease]], [[neurofibromatosis]] type 1, and [[tuberous sclerosis]]; overgrowth syndromes such as [[Sotos syndrome]] (cerebral gigantism), [[Weaver syndrome]], [[Simpson–Golabi–Behmel syndrome]] (bulldog syndrome), and [[macrocephaly-capillary malformation]] (M-CMTC) syndrome; neurocardiofacial-cutaneous syndromes such as [[Noonan syndrome]], [[Costello syndrome]], [[Gorlin syndrome]],<ref>{{Cite web |url=http://www.gorlinsyndrome.org/EduDocs/General/Nevoid%20Basal%20Cell%20Carcinoma%20Syndrome.pdf |title=Archived copy |access-date=2015-05-04 |archive-url=https://web.archive.org/web/20151009061914/http://www.gorlinsyndrome.org/EduDocs/General/Nevoid%20Basal%20Cell%20Carcinoma%20Syndrome.pdf |archive-date=2015-10-09 |url-status=dead }}</ref> (also known as basal cell nevus syndrome) and [[cardiofaciocutaneous syndrome]]; [[Fragile X syndrome]]; [[leukodystrophies]] (brain [[white matter]] degeneration) such as [[Alexander disease]], [[Canavan disease]], and [[megalencephalic leukoencephalopathy with subcortical cysts]]; and [[glutaric aciduria type 1]] and [[D-2-hydroxyglutaric aciduria]].<ref name=Williams/>

At one end of the genetic spectrum, duplications of chromosomes have been found to be related to autism and macrocephaly; at the other end, deletions of chromosomes have been found to be related to [[schizophrenia]] and [[microcephaly]].<ref>{{cite journal|author=Crespi|display-authors=etal|year=2010|title=Comparative genomics of autism and schizophrenia|journal=PNAS|volume=107|issue=Suppl 1 |pages=1736–1741|doi=10.1073/pnas.0906080106|pmc=2868282|pmid=19955444|doi-access=free}}</ref><ref>{{cite journal | title = Rare chromosomal deletions and duplications increase risk of schizophrenia; The International Schizophrenia Consortium; | journal = Nature | volume = 455| issue = 7210| pages = 237–241 | doi = 10.1038/nature07239 | pmid=18668038 | date=September 2008 | pmc=3912847| author1 = International Schizophrenia Consortium }}</ref><ref>{{cite journal | author = Dumas L. | author2 = Sikela J.M. | year = 2009 | title = DUF1220 Domains, Cognitive Disease, and Human Brain Evolution | journal = Cold Spring Harb. Symp. Quant. Biol.| volume =  74| pages =  375–82| doi = 10.1101/sqb.2009.74.025 | pmid=19850849 | pmc=2902282}}</ref>

Environmental events associated with macrocephaly include infection, neonatal [[intraventricular hemorrhage]] (bleeding within the infant brain), [[subdural hematoma]] (bleeding beneath the outer lining of the brain), [[subdural effusion]] (collection of fluid beneath the outer lining of the brain), and [[arachnoid cyst]]s (cysts on the brain surface).<ref name=Williams/>

In research, cranial height or brain imaging may be used to determine intracranial volume more accurately.<ref name=Williams>{{cite journal |journal= Am J Med Genet A |date=2008 |volume=146A |issue=16 |pages=2023–37 |title= Genetic disorders associated with macrocephaly |vauthors= Williams CA, Dagli A, Battaglia A |doi=10.1002/ajmg.a.32434 |pmid=18629877|s2cid=205309800 |doi-access=free }}</ref>

Below is a list of conditions featuring macrocephaly from [[NCBI]]'s MedGen:<ref>{{Cite web |title=Macrocephaly (Concept Id: C2243051) - MedGen - NCBI |url=https://www.ncbi.nlm.nih.gov/medgen/745757 |access-date=2023-06-30 |website=www.ncbi.nlm.nih.gov |language=en}}</ref>

* [[Achondroplasia]]
* [[Acrocallosal syndrome]]
* [[Adams-Oliver syndrome]] 
* [[Adenosine kinase]] deficiency
* [[Antley-Bixler syndrome]]
* Autosomal dominant [[Kenny-Caffey syndrome]]
* [[Malignant infantile osteopetrosis|Autosomal recessive osteopetrosis]]
* [[Axenfeld-Rieger anomaly]]
* [[B4GALT1]]-[[congenital disorder of glycosylation]]
* [[Bardet-Biedl syndrome]] 
* [[Brittle cornea syndrome]] 
* [[Camptomelic dysplasia]]
* [[Cardio-facio-cutaneous syndrome]]
* [[Cobblestone lissencephaly]] without muscular or ocular involvement
* [[Coffin-Siris syndrome]]
* [[Cohen-Gibson syndrome]]
* [[Cole-Carpenter syndrome]] 
* [[Congenital disorder of glycosylation]], type Iw, autosomal dominant
* [[Agenesis of corpus callosum|Corpus callosum, agenesis of]]
* [[Costello syndrome]]
* [[Cowden syndrome]] 
* [[Craniodiaphyseal dysplasia]], autosomal dominant
* [[Cranioectodermal dysplasia]] 
* [[Craniometaphyseal dysplasia]]
* [[Craniosynostosis]]
* [[D-2-hydroxyglutaric aciduria]]
* Deficiency of [[alpha-mannosidase]]
* [[Desmosterolosis]]
* [[Donnai-Barrow syndrome]]
* [[Early-onset parkinsonism-intellectual disability syndrome]]
* [[Ehlers-Danlos syndrome]], spondylodysplastic type
* [[Epidermolysis bullosa simplex]]
* [[Fragile X syndrome]]
* [[Giant axonal neuropathy]]
* [[Glutaric aciduria]], type 1
* [[Gorlin syndrome]]
* [[Greenberg dysplasia]]
* [[Greig cephalopolysyndactyly syndrome]]
* [[Hamartoma]] of [[hypothalamus]]
* [[Holoprosencephaly]]
* [[Hurler syndrome]]
[[File:Peterson 283.jpg|thumb|Macrocephaly from hydrocephalus]]
* [[Hydrocephalus]], nonsyndromic, autosomal recessive
* [[Hypochondroplasia]]
* [[Hypophosphatemic rickets]] and [[hyperparathyroidism]]
* [[Hypothyroidism]], congenital, nongoitrous
* Ito [[hypomelanosis]]
* [[Joubert syndrome]]
* [[Keipert syndrome]]
* [[Legius syndrome]]
* [[LEOPARD syndrome]] 
* [[Lethal congenital contracture syndrome]] 
* [[MASA syndrome]]
[[File:Stoddart 79.jpg|thumb|Macrocephaly from megalencephaly]]
* [[Megalencephaly]], autosomal dominant
* [[Megalocornea-intellectual disability syndrome]]
* [[MGAT2]]-[[congenital disorder of glycosylation]]
* [[MOMO syndrome]]
* [[Mucopolysaccharidosis type 6]]
* [[Sly syndrome|Mucopolysaccharidosis type 7]]
* [[Mucopolysaccharidosis II|Mucopolysaccharidosis, MPS-II]]
* [[Mucopolysaccharidosis III|Mucopolysaccharidosis, MPS-III-D]]
* [[Muenke syndrome]]
* [[Multiple acyl-CoA dehydrogenase deficiency]]
* [[Multiple congenital anomalies-hypotonia-seizures syndrome]]
* [[Multiple epiphyseal dysplasia]], Al-Gazali type
* [[Myhre syndrome]]
* [[Neurofibromatosis type 1|Neurofibromatosis, type 1]]
* [[Neurofibromatosis-Noonan syndrome]]
* [[Niemann-Pick disease]], type A
* [[Noonan syndrome]]
* [[Opsismodysplasia]]
* [[Optic atrophy]]
* [[Osteopathia striata]] with cranial [[Sclerosis (medicine)|sclerosis]]
* [[Pallister-Killian syndrome]]
* [[Parietal foramina]] 
* Parietal foramina with [[cleidocranial dysplasia]]
* [[Pelger-Huët anomaly]]
* [[Zellweger syndrome|Peroxisome biogenesis disorder 1A (Zellweger)]]
* [[Peroxisome biogenesis disorder]] 4B
* [[Phelan-McDermid syndrome]]
* [[Plasminogen]] deficiency, type I
* [[Primrose syndrome]]
* [[Proteus syndrome]]
* [[Ritscher-Schinzel syndrome]] 
* [[Robinow syndrome]]
* [[Sandhoff disease]]
* [[Schneckenbecken dysplasia]]
* [[Sclerosteosis]] 
* Severe [[X-linked myotubular myopathy]]
* [[Sialuria]]
* [[Simpson-Golabi-Behmel syndrome]] 
* [[Snijders Blok-Campeau syndrome]]
* [[Sotos syndrome]] 
* [[Sturge-Weber syndrome]]
* [[Sulfite oxidase deficiency]] due to [[molybdenum cofactor deficiency]]
* [[Symphalangism]] with multiple anomalies of hands and feet
* Syndromic [[X-linked intellectual disability]]
* [[Thanatophoric dysplasia]] type 1
* [[Vanishing white matter disease]]
* [[Weaver syndrome]]
* X-linked dominant [[chondrodysplasia]], Chassaing-Lacombe type
* X-linked hydrocephalus syndrome
* [[X-linked intellectual disability]] with [[marfanoid habitus]]
* [[Zimmermann-Laband syndrome]] 
* [[ZTTK syndrome]]