WordNet

an abnormally large head; differs from hydrocephalus because there is no increased intracranial pressure and the overgrowth is symmetrical (同)megacephaly, megalocephaly

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出典(authority):フリー百科事典『ウィキペディア（Wikipedia）』「2016/02/22 07:14:26」(JST)

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Macrocephaly is a condition in which the head is abnormally large (circumference 2.5 standard deviations above normal^{[contradiction]} for weight and gender); this includes the scalp, the cranial bone, and the contents of the cranium.

Causes

Macrocephaly may be pathologic, but many people with an unusually large head and large skull are healthy. Pathologic macrocephaly may be due to megalencephaly (enlarged brain), hydrocephalus (water on the brain), 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 can be caused by congenital anatomic abnormalities, genetic conditions, or by environmental events.^[1]

Many genetic conditions are associated with macrocephaly, including familial macrocephaly related to the holgate gene, autism, 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,^[2] (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.^[1]

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.^[3]^[4]^[5]

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 cysts (cysts on the brain surface).^[1]

Diagnosis

Macrocephaly is customarily diagnosed if head circumference is greater than two standard deviations (SDs) above the mean.^{[contradiction]} Relative macrocephaly occurs if the measure is less than two SDs above the mean, but is disproportionately above that when ethnicity and stature are considered. In research, cranial height or brain imaging is also used to determine intracranial volume more accurately.^[1]

References

^ ^a ^b ^c ^d Williams CA, Dagli A, Battaglia A (2008). "Genetic disorders associated with macrocephaly". Am J Med Genet A 146A (16): 2023–37. doi:10.1002/ajmg.a.32434. PMID 18629877.
^ http://www.gorlinsyndrome.org/EduDocs/General/Nevoid%20Basal%20Cell%20Carcinoma%20Syndrome.pdf
^ Crespi; et al. (2010). "Comparative genomics of autism and schizophrenia". PNAS 107: 1736–1741. doi:10.1073/pnas.0906080106. PMC 2868282. PMID 19955444.
^ "Rare chromosomal deletions and duplications increase risk of schizophrenia; The International Schizophrenia Consortium;". Nature 455: 237–241. September 2008. doi:10.1038/nature07239. PMC 3912847. PMID 18668038.
^ Dumas L., Sikela J.M. (2009). "DUF1220 Domains, Cognitive Disease, and Human Brain Evolution". Cold Spring Harb. Symp. Quant. Biol. 74: 375–82. doi:10.1101/sqb.2009.74.025. PMC 2902282. PMID 19850849.

External links

GeneReviews/NCBI/NIH/UW entry on PTEN Hamartoma Tumor Syndrome (PHTS)
GeneReviews/NCBI/NIH/UW entry on 9q22.3 Microdeletion

UpToDate Contents

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1. 幼児および小児における巨頭症の病因および評価 etiology and evaluation of macrocephaly in infants and children
2. 毛細血管奇形（ポートワイン母斑）：臨床的特徴、診断、および関連する症候群 capillary malformations port wine stains clinical features diagnosis and associated syndromes
3. カウデン症候群などのPTEN過誤腫症候群 pten hamartoma tumor syndrome including cowden syndrome
4. 微細欠失症候群（12番～22番染色体） microdeletion syndromes chromosomes 12 to 22
5. 自閉症スペクトラム障害の臨床的特徴 clinical features of autism spectrum disorders

English Journal

Detection of a mosaic PIK3CA mutation in dental DNA from a child with megalencephaly capillary malformation syndrome.

McDermott JH1, Byers H, Clayton-Smith J.
Clinical dysmorphology.Clin Dysmorphol.2016 Jan;25(1):16-8. doi: 10.1097/MCD.0000000000000099.
The megalencephaly capillary malformation syndrome (MCAP, OMIM 602501) is known to be associated with mosaic mutations in PIK3CA occurring during embryogenesis. Standard sequencing technologies are relatively poor at indentifying sequence changes that only affect a small percentage of cells, and the
PMID 26351730

Mouse models of human PIK3CA-related brain overgrowth have acutely treatable epilepsy.

Roy A1, Skibo J1, Kalume F1, Ni J2, Rankin S3, Lu Y4, Dobyns WB1, Mills GB4, Zhao JJ5, Baker SJ3, Millen KJ1.
eLife.Elife.2015 Dec 3;4. pii: e12703. doi: 10.7554/eLife.12703. [Epub ahead of print]
Mutations in the catalytic subunit of phosphoinositide 3-kinase (PIK3CA) and other PI3K-AKT pathway components have been associated with cancer and a wide spectrum of brain and body overgrowth. In the brain, the phenotypic spectrum of PIK3CA-related segmental overgrowth includes bilateral dysplastic
PMID 26633882

Interaction between a domain of a negative regulator of the RAS-ERK pathway, SPRED1, and the GTPase-Activating Protein-Related Domain of neurofibromin is implicated in Legius Syndrome and Neurofibromatosis Type 1.

Hirata Y1, Brems H2, Suzuki M1, Kanamori M1, Okada M1, Morita R1, Llano-Rivas I3, Ose T4, Messiaen L5, Legius E2, Yoshimura A6.
The Journal of biological chemistry.J Biol Chem.2015 Dec 3. pii: jbc.M115.703710. [Epub ahead of print]
Constitutional heterozygous loss-of-function mutations in the SPRED1 gene cause a phenotype known as Legius syndrome, which consists of symptoms of multiple cafe-au-lait macules, axillary freckling, learning disabilities and macrocephaly. Legius syndrome resembles a mild neurofibromatosis type 1 (NF
PMID 26635368

Japanese Journal

Pure Choriocarcinoma of the Ovary in Silver-Russell Syndrome

Haruma Tomoko,Ogawa Chikako,Nishida Takeshi,Kusumoto Tomoyuki,Nakamura Keiichiro,Seki Noriko,Katayama Takaaki,Hiramatsu Yuji
Acta Medica Okayama 69(3), 183-188, 2015-06
… Silver-Russell syndrome (SRS) is a rare congenital developmental disorder characterized by pre- and postnatal growth failure, relative macrocephaly, a triangular face, hemihypotrophy, and fifth-finger clinodactyly. …
NAID 120005621913

臨床研究・症例報告無症状の母体から出生し,水頭症,頭囲拡大を認めた新生児ループスの1例

安江志保,門井絵美,豊島由佳 [他]
小児科臨床 67(11), 2115-2119, 2014-11
NAID 40020241817

Clinical and genetic spectrum of 18 unrelated Korean patients with Sotos syndrome : frequent 5q35 microdeletion and identification of four novel NSD1 mutations

SOHN Young Bae,LEE Cha Gon,KO Jung Min,YANG Jung-Ah,YUN Jun-No,JUNG Eun-Jung,JIN Hyun-Seok,PARK Sang-Jin,JEONG Seon Yong
Journal of human genetics 58(2), 73-77, 2013-02-01
NAID 10031156427

Related Pictures

★リンクテーブル★

リンク元	「大頭症」「巨頭症」

「大頭症」

Macrocephaly
	An MRI of a patient with benign familial macrocephaly (male with head circumference > 60cm)
Classification and external resources
Specialty	medical genetics
ICD-10	Q75.3
ICD-9-CM	756.0
OMIM	248000
DiseasesDB	22519
MedlinePlus	003305
MeSH	D058627
	[edit on Wikidata]