Mutations of AKT3 are associated with a wide spectrum of developmental disorders including extreme megalencephaly

Mutations of genes 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 polymicrogyria). Mutations of the AKT3 gene have been repor...

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Elmentve itt :
Bibliográfiai részletek
Szerzők: Alcantara Diana
Timms Andrew E.
Gripp Karen
Baker Laura
Park Kaylee
Sztriha László
Zombor Melinda
Caluseriu Oana
Mesterman Ronit
Van Allen Margot I.
Jacquinet Adeline
Ygberg Sofia
Bernstein Jonathan A.
Wenger Aaron M.
Guturu Harendra
Dokumentumtípus: Cikk
Megjelent: Oxford University Press 2017
Sorozat:BRAIN 140 No. 10
doi:10.1093/brain/awx203

mtmt:3324478
Online Access:http://publicatio.bibl.u-szeged.hu/12877
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520 3 |a Mutations of genes 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 polymicrogyria). Mutations of the AKT3 gene have been reported in a few individuals with brain malformations, to date. Therefore, our understanding regarding the clinical and molecular spectrum associated with mutations of this critical gene is limited, with no clear genotype-phenotype correlations. We sought to further delineate this spectrum, study levels of mosaicism and identify genotype-phenotype correlations of AKT3-related disorders. We performed targeted sequencing of AKT3 on individuals with these phenotypes by molecular inversion probes and/or Sanger sequencing to determine the type and level of mosaicism of mutations. We analysed all clinical and brain imaging data of mutation-positive individuals including neuropathological analysis in one instance. We performed ex vivo kinase assays on AKT3 engineered with the patient mutations and examined the phospholipid binding profile of pleckstrin homology domain localizing mutations. We identified 14 new individuals with AKT3 mutations with several phenotypes dependent on the type of mutation and level of mosaicism. Our comprehensive clinical characterization, and review of all previously published patients, broadly segregates individuals with AKT3 mutations into two groups: patients with highly asymmetric cortical dysplasia caused by the common p.E17K mutation, and patients with constitutional AKT3 mutations exhibiting more variable phenotypes including bilateral cortical malformations, polymicrogyria, periventricular nodular heterotopia and diffuse megalencephaly without cortical dysplasia. All mutations increased kinase activity, and pleckstrin homology domain mutants exhibited enhanced phospholipid binding. Overall, our study shows that activating mutations of the critical AKT3 gene are associated with a wide spectrum of brain involvement ranging from focal or segmental brain malformations (such as hemimegalencephaly and polymicrogyria) predominantly due to mosaic AKT3 mutations, to diffuse bilateral cortical malformations, megalencephaly and heterotopia due to constitutional AKT3 mutations. We also provide the first detailed neuropathological examination of a child with extreme megalencephaly due to a constitutional AKT3 mutation. This child has one of the largest documented paediatric brain sizes, to our knowledge. Finally, our data show that constitutional AKT3 mutations are associated with megalencephaly, with or without autism, similar to PTEN-related disorders. Recognition of this broad clinical and molecular spectrum of AKT3 mutations is important for providing early diagnosis and appropriate management of affected individuals, and will facilitate targeted design of future human clinical trials using PI3K-AKT pathway inhibitors. 
700 0 1 |a Timms Andrew E.  |e aut 
700 0 1 |a Gripp Karen  |e aut 
700 0 1 |a Baker Laura  |e aut 
700 0 1 |a Park Kaylee  |e aut 
700 0 1 |a Sztriha László  |e aut 
700 0 1 |a Zombor Melinda  |e aut 
700 0 1 |a Caluseriu Oana  |e aut 
700 0 1 |a Mesterman Ronit  |e aut 
700 0 2 |a Van Allen Margot I.  |e aut 
700 0 2 |a Jacquinet Adeline  |e aut 
700 0 2 |a Ygberg Sofia  |e aut 
700 0 2 |a Bernstein Jonathan A.  |e aut 
700 0 2 |a Wenger Aaron M.  |e aut 
700 0 2 |a Guturu Harendra  |e aut 
856 4 0 |u http://publicatio.bibl.u-szeged.hu/12877/1/awx203_Zombor_Melinda_2_u.pdf  |z Dokumentum-elérés