Summary: A congenital abnormality in which the occipitofrontal circumference is greater than two standard deviations above the mean for a given age. It is associated with HYDROCEPHALUS; SUBDURAL EFFUSION; ARACHNOID CYSTS; or is part of a genetic condition (e.g., ALEXANDER DISEASE; SOTOS SYNDROME).

Top Publications

  1. Nakamura K, Kato M, Tohyama J, Shiohama T, Hayasaka K, Nishiyama K, et al. AKT3 and PIK3R2 mutations in two patients with megalencephaly-related syndromes: MCAP and MPPH. Clin Genet. 2014;85:396-8 pubmed publisher
  2. Pavone P, Praticò A, Rizzo R, Corsello G, Ruggieri M, Parano E, et al. A clinical review on megalencephaly: A large brain as a possible sign of cerebral impairment. Medicine (Baltimore). 2017;96:e6814 pubmed publisher
    b>Megalencephaly and macrocephaly present with a head circumference measurement 2 standard deviations above the age-related mean...
  3. Koh J, Lim J, Byun H, Yoo M. Abnormalities in the zinc-metalloprotease-BDNF axis may contribute to megalencephaly and cortical hyperconnectivity in young autism spectrum disorder patients. Mol Brain. 2014;7:64 pubmed publisher
    ..ZMB) axis in the forebrain plays a pivotal role in the development of hyperconnectivity and megalencephaly in ASD...
  4. Platt R, Zhou Y, Slaymaker I, Shetty A, Weisbach N, Kim J, et al. Chd8 Mutation Leads to Autistic-like Behaviors and Impaired Striatal Circuits. Cell Rep. 2017;19:335-350 pubmed publisher
    ..These results support a mechanism linking chromatin modification to striatal dysfunction and the molecular pathology of ASD. ..
  5. Leiter S, Parker V, Welters A, Knox R, Rocha N, Clark G, et al. Hypoinsulinaemic, hypoketotic hypoglycaemia due to mosaic genetic activation of PI3-kinase. Eur J Endocrinol. 2017;177:175-186 pubmed publisher
    ..Three patients with megalencephaly, diffuse asymmetric overgrowth, hypoketotic, hypoinsulinaemic hypoglycaemia and no AKT2 mutation ..
  6. Pettersson M, Viljakainen H, Loid P, Mustila T, Pekkinen M, Armenio M, et al. Copy Number Variants Are Enriched in Individuals With Early-Onset Obesity and Highlight Novel Pathogenic Pathways. J Clin Endocrinol Metab. 2017;102:3029-3039 pubmed publisher
    ..The involved genes might provide insights into pathogenic mechanisms and involved cellular pathways. These findings highlight the importance of CNV screening in children with early-onset obesity. ..
  7. Peterman C, Vadeboncoeur S, Mulliken J, Fishman S, Liang M. Wilms tumor screening in diffuse capillary malformation with overgrowth and macrocephaly-capillary malformation: A retrospective study. J Am Acad Dermatol. 2017;77:874-878 pubmed publisher
    ..Screening is probably unnecessary in DCMO unless there is associated hemihypertrophy. Although there were no cases in our cohort, there are 2 reports of M-CM associated with Wilms tumor in the literature. ..
  8. Alcantara D, Timms A, Gripp K, Baker L, Park K, Collins S, et al. Mutations of AKT3 are associated with a wide spectrum of developmental disorders including extreme megalencephaly. Brain. 2017;140:2610-2622 pubmed publisher
    ..within the phosphatidylinositol-3-kinase (PI3K)-AKT-MTOR pathway are well known causes of brain overgrowth (megalencephaly) as well as segmental cortical dysplasia (such as hemimegalencephaly, focal cortical dysplasia and ..