Orphanet: Megalencephaly

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Disease definition

A rare central nervous system malformation characterized by an abnormally large brain, accompanied by abnormal head circumference measurements evident at birth or developing over the first years of life. The condition can be unilateral or bilateral and affects males more often than females. There is no typical pattern of symptoms, but mental retardation, seizures, and other neurologic abnormalities have been reported.


Classification level: Disorder
  • Synonym(s):
    • Macroencephaly
  • Prevalence: -
  • Inheritance: -
  • Age of onset: Antenatal, Neonatal
  • ICD-10: Q04.5
  • ICD-11: LA05.1
  • OMIM: 155350  248000
  • UMLS: C2720434
  • MeSH: -
  • GARD: -
  • MedDRA: 10050183
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