Caption = An MRI of a patient with benign familial macrocephaly (male with head circumference > 60cm)
DiseasesDB = 22519
ICD10 = ICD10|Q|75|3|q|65
ICD9 = ICD9|756.0
OMIM = 248000
MedlinePlus = 003305
eMedicineSubj =
eMedicineTopic =
MeshID =

Macrocephaly (from the ancient Greek "μακρό-" "macro-" long- + "-κέφαλος" "-kephalos" -head), occurs when the head is abnormally large; this includes the scalp, the cranial bone, and the contents of the cranium.


Macrocephaly may be due to megalencephaly (enlarged brain), to hydrocephalus (water on the brain), cranial hyperostosis (bone overgrowth), and other conditions. It is called "syndromic" when it is associated with any other noteworthy condition, and "non-syndromic" otherwise. It can be caused by genetic conditions or by environmental events.

Many genetic conditions are associated with macrocephaly, including familial macrocephaly, 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; neuro-cardio-facial-cutaneous syndromes such as Noonan syndrome, Costello 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.

Environmental events associated with macrocephaly include infection, neonatal intraventricular hemorrhage (bleeding within the infant brain), subdural effusion (collection of pus beneath the outer lining of the brain), and arachnoid cysts (cysts on the brain surface).


Macrocephaly is customarily diagnosed if head circumference is greater than 2 standard deviations (SD) above the mean. Relative macrocephaly occurs if the measure is less than 2 SD above the mean but is disproportionately above that when ethnicity and stature are considered. In research, cranial height or brain imaging are also used to determine intracranial volume more accurately.cite journal |journal= Am J Med Genet A |date=2008 |volume=146A |issue=16 |pages=2023–37 |title= Genetic disorders associated with macrocephaly |author= Williams CA, Dagli A, Battaglia A |doi=10.1002/ajmg.a.32434 |pmid=18629877]

ee also

* Microcephaly


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Look at other dictionaries:

  • macrocephaly — n. THe condition of having an unusually large head; it differs from {hydrocephalus} because there is no increase intracranial pressure and the overgrowth is symmetrical. Syn: megacephaly, megalocephaly. [WordNet 1.5] …   The Collaborative International Dictionary of English

  • macrocephaly — [mak΄rō sef′ə lē] n. 〚 MACRO + CEPHALY〛 a condition in which the head or cranial capacity is abnormally large: opposed to MICROCEPHALY macrocephalous adj. macrocephalic [mak΄rəsə fal′ik] * * * …   Universalium

  • macrocephaly — [mak΄rō sef′ə lē] n. [ MACRO + CEPHALY] a condition in which the head or cranial capacity is abnormally large: opposed to MICROCEPHALY macrocephalous adj. macrocephalic [mak΄rəsə fal′ik] …   English World dictionary

  • macrocephaly — noun an abnormally large head; differs from hydrocephalus because there is no increased intracranial pressure and the overgrowth is symmetrical • Syn: ↑megacephaly, ↑megalocephaly • Derivationally related forms: ↑macrocephalic • Hypernyms:… …   Useful english dictionary

  • Macrocephaly, multiple lipomas, and hemangiomas — Bannayan syndrome, a genetic disease characterized by macrocephaly (enlarged head), multiple lipomas (benign fatty tumors) and hemangiomas (benign blood vessel tumors). The macrocephaly occurs without enlargement of the cerebral ventricles. There …   Medical dictionary

  • macrocephaly — abnormal enlargement of the head …   Dictionary of ichthyology

  • macrocephaly — noun A condition in which the head is abnormally large …   Wiktionary

  • macrocephaly — mac·ro·ceph·a·ly sef ə lē n, pl lies the quality or state of being macrocephalous * * * (megalocephaly) n. abnormal largeness of the head in relation to the rest of the body. Compare microcephaly. * * * mac·ro·ceph·a·ly (mak″ro sefґə… …   Medical dictionary

  • macrocephaly — mækrəʊ sɪfÉ™lɪ n. excessive largeness of the head, megalocephaly …   English contemporary dictionary

  • macrocephaly — mac·ro·ceph·a·ly …   English syllables

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