Megalencephaly
Megalencephaly (or macrencephaly; abbreviated MEG) is a growth development disorder in which the brain is abnormally large. It is characterized by a brain with an average weight that is 2.5 standard deviations above the mean of the general population. Approximately 1 out of 50 children (2%) are said to have the characteristics of megalencephaly in the general population.
| Megalencephaly | |
|---|---|
| Other names | Macrencephaly |
| MRI images showing megalencephaly in four family members who all have unusually large skulls (the family is affected by an autosomal recessive syndrome caused by a KIF7 mutation that induces multiple epiphyseal dysplasia) | |
| Specialty | Medical genetics, neurology, pediatrics |
| Usual onset | Congenital |
| Duration | Long-term |
A mutation in the PI3K-AKT pathway is believed to be the primary cause of brain proliferation and ultimately the root cause of megalencephaly. This mutation has produced a classification of brain overdevelopment that consists of two syndromes including megalencephaly-capillary malformation (MCAP) and megalencephaly-polydactyly-polymicrogyria-hydrocephalus (MPPH). Megalencephaly is usually diagnosed at birth and is confirmed with an MRI.
There are several neuropsychiatric disorders linked with megalencephaly; however, studies have shown that autism is the most prevalent association with the malformation of MEG. Although no treatment currently exists for megalencephaly, management methods are focused at reducing deficits linked with autism. Most recent research is targeted at creating inhibitors to reduce the mutational pathway that causes megalencephaly.