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Dysplastic megalencephaly

MedGen UID:
1815079
•Concept ID:
C5706173
•
Congenital Abnormality
Synonym: Bilateral hemimegalencephaly
 
HPO: HP:0034329

Definition

A congenital brain malformation characterized by marked overgrowth and dysplasia affecting one or both cerebral hemispheres, and, in some cases, subcortical brain regions as well. The presence of dysplasia in dysplastic megalencephaly distinguishes it from other forms of generalized megalencephaly. [from HPO]

Term Hierarchy

CClinical test,  RResearch test,  OOMIM,  GGeneReviews,  VClinVar  
  • CROGVDysplastic megalencephaly

Professional guidelines

PubMed

PIK3CA-related overgrowth spectrum (PROS): diagnostic and testing eligibility criteria, differential diagnosis, and evaluation.
Keppler-Noreuil KM, Rios JJ, Parker VE, Semple RK, Lindhurst MJ, Sapp JC, Alomari A, Ezaki M, Dobyns W, Biesecker LG
Am J Med Genet A 2015 Feb;167A(2):287-95. Epub 2014 Dec 31 doi: 10.1002/ajmg.a.36836. PMID: 25557259Free PMC Article

Recent clinical studies

Etiology

Molecular characterization of 13 patients with PIK3CA-related overgrowth spectrum using a targeted deep sequencing approach.
de Kock L, Cuillerier A, Gillespie M, Couse M, Hartley T, Mears W, Bernier FP, Chudley AE, Frosk P, Nikkel SM, Innes AM, Lauzon J, Thomas M, Guerin A, Armour CM, Weksberg R, Scott JN, Watkins D, Harvey S, Cytrynbaum C; Care4Rare Canada Consortium, Kernohan KD, Boycott KM
Am J Med Genet A 2024 Mar;194(3):e63466. Epub 2023 Nov 10 doi: 10.1002/ajmg.a.63466. PMID: 37949664
PIK3CA-related overgrowth spectrum (PROS): diagnostic and testing eligibility criteria, differential diagnosis, and evaluation.
Keppler-Noreuil KM, Rios JJ, Parker VE, Semple RK, Lindhurst MJ, Sapp JC, Alomari A, Ezaki M, Dobyns W, Biesecker LG
Am J Med Genet A 2015 Feb;167A(2):287-95. Epub 2014 Dec 31 doi: 10.1002/ajmg.a.36836. PMID: 25557259Free PMC Article

Diagnosis

Molecular characterization of 13 patients with PIK3CA-related overgrowth spectrum using a targeted deep sequencing approach.
de Kock L, Cuillerier A, Gillespie M, Couse M, Hartley T, Mears W, Bernier FP, Chudley AE, Frosk P, Nikkel SM, Innes AM, Lauzon J, Thomas M, Guerin A, Armour CM, Weksberg R, Scott JN, Watkins D, Harvey S, Cytrynbaum C; Care4Rare Canada Consortium, Kernohan KD, Boycott KM
Am J Med Genet A 2024 Mar;194(3):e63466. Epub 2023 Nov 10 doi: 10.1002/ajmg.a.63466. PMID: 37949664
Dysplasia and overgrowth: magnetic resonance imaging of pediatric brain abnormalities secondary to alterations in the mechanistic target of rapamycin pathway.
Shrot S, Hwang M, Stafstrom CE, Huisman TAGM, Soares BP
Neuroradiology 2018 Feb;60(2):137-150. Epub 2017 Dec 26 doi: 10.1007/s00234-017-1961-5. PMID: 29279945
PIK3CA-related overgrowth spectrum (PROS): diagnostic and testing eligibility criteria, differential diagnosis, and evaluation.
Keppler-Noreuil KM, Rios JJ, Parker VE, Semple RK, Lindhurst MJ, Sapp JC, Alomari A, Ezaki M, Dobyns W, Biesecker LG
Am J Med Genet A 2015 Feb;167A(2):287-95. Epub 2014 Dec 31 doi: 10.1002/ajmg.a.36836. PMID: 25557259Free PMC Article

Prognosis

Dysplastic megalencephaly phenotype presenting with prenatal high-output cardiac failure.
Del Campos Braojos F, Guimaraes CVA
Pediatr Radiol 2018 Aug;48(8):1172-1177. Epub 2018 Mar 28 doi: 10.1007/s00247-018-4121-0. PMID: 29594439
PI3K/AKT pathway mutations cause a spectrum of brain malformations from megalencephaly to focal cortical dysplasia.
Jansen LA, Mirzaa GM, Ishak GE, O'Roak BJ, Hiatt JB, Roden WH, Gunter SA, Christian SL, Collins S, Adams C, Rivière JB, St-Onge J, Ojemann JG, Shendure J, Hevner RF, Dobyns WB
Brain 2015 Jun;138(Pt 6):1613-28. Epub 2015 Feb 25 doi: 10.1093/brain/awv045. PMID: 25722288Free PMC Article

Clinical prediction guides

PI3K/AKT pathway mutations cause a spectrum of brain malformations from megalencephaly to focal cortical dysplasia.
Jansen LA, Mirzaa GM, Ishak GE, O'Roak BJ, Hiatt JB, Roden WH, Gunter SA, Christian SL, Collins S, Adams C, Rivière JB, St-Onge J, Ojemann JG, Shendure J, Hevner RF, Dobyns WB
Brain 2015 Jun;138(Pt 6):1613-28. Epub 2015 Feb 25 doi: 10.1093/brain/awv045. PMID: 25722288Free PMC Article

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