Name = PAGENAME
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
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, PTENmutations such as Cowden disease, neurofibromatosistype 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 matterdegeneration) such as Alexander disease, Canavan disease, and megalencephalic leukoencephalopathy with subcortical cysts; and glutaric aciduria type 1and D-2-hydroxyglutaric aciduria.
Environmental events associated with macrocephaly include infection, neonatal
intraventricular hemorrhage(bleeding within the infant brain), subdural effusion (collection of pusbeneath 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]
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