Hemimegalencephaly

Rare MALFORMATIONS OF CORTICAL DEVELOPMENT, GROUP I characterized by the enlargement of one side of the brain. It is associated with seizures, partial paralysis, and mental retardation.

Also Known As:

Unilateral Macrocephaly; Unilateral Megalencephaly; Hemimegalencephalies; Macrocephalies, Unilateral; Macrocephaly, Unilateral; Megalencephalies, Unilateral; Megalencephaly, Unilateral; Unilateral Macrocephalies; Unilateral Megalencephalies

Networked: 111 relevant articles (6 outcomes, 4 trials/studies)

Relationship Network

Disease Context: Research Results

Related Diseases

1.	Seizures (Absence Seizure)
2.	Status Epilepticus (Complex Partial Status Epilepticus)
3.	Infantile Spasms (West Syndrome)
4.	Atrophy
5.	Focal Cortical Dysplasia

Experts

1.	Crino, Peter B: 8 articles (01/2022 - 04/2002)
2.	Mathern, Gary W: 7 articles (12/2021 - 12/2005)
3.	Vinters, Harry V: 6 articles (01/2021 - 04/2002)
4.	Aronica, Eleonora: 5 articles (01/2019 - 12/2004)
5.	Salamon, Noriko: 4 articles (01/2021 - 12/2005)
6.	Sugai, Kenji: 4 articles (06/2019 - 12/2009)
7.	Chang, Julia W: 3 articles (01/2021 - 02/2006)
8.	Poduri, Annapurna: 3 articles (01/2021 - 06/2014)
9.	Sasaki, Masayuki: 3 articles (06/2019 - 12/2009)
10.	Otsuki, Taisuke: 3 articles (05/2017 - 12/2009)

Drugs and Biologics

Drugs and Important Biological Agents (IBA) related to Hemimegalencephaly:

1.	Ketamine FDA LinkGeneric 03/01/2022 - "Efficacy of Ketamine Use in Refractory Status Epilepticus Associated With Hemimegalencephaly."
2.	Inosine Monophosphate (IMP)IBA 11/01/1994 - "Serial IMP-SPECT and EEG studies in an infant with hemimegalencephaly." 11/01/1994 - "These serial changes of IMP uptake on SPECT seemed to reflect either changes in epileptic activity or maturational changes in cerebral perfusion in hemimegalencephaly." 11/01/1990 - "Hemimegalencephaly: clinical, EEG, neuroimaging, and IMP-SPECT correlation." 11/01/1990 - "Iofetamine-single photon emission computed tomography (IMP-SPECT) was performed on 2 girls (5 1/2 and 6 years of age) with histories of intractable seizures, developmental delay, and unilateral hemiparesis secondary to hemimegalencephaly. "
3.	Glucose (Dextrose)FDA LinkGeneric 01/01/1993 - "We performed positron emission tomographic (PET) studies with 2-deoxy-2[18F]fluoro-D-glucose in 8 children with hemimegalencephaly (HME). " 12/01/2010 - "Unique discrepancy between cerebral blood flow and glucose metabolism in hemimegalencephaly."
4.	Member 2 Solute Carrier Family 12IBA 03/02/2007 - "In the present study the expression and cell-specific distribution of Na+-K+-2Cl--cotransporter (NKCC1) and K+-Cl--cotransporter (KCC2) were studied immunocytochemically in different developmental lesions, including focal cortical dysplasia (FCD) type IIB (n=9), hemimegalencephaly (HMEG, n=6) and ganglioglioma (GG, n=9) from patients with medically intractable epilepsy and in age-matched controls. "
5.	K Cl- CotransportersIBA 03/02/2007 - "In the present study the expression and cell-specific distribution of Na+-K+-2Cl--cotransporter (NKCC1) and K+-Cl--cotransporter (KCC2) were studied immunocytochemically in different developmental lesions, including focal cortical dysplasia (FCD) type IIB (n=9), hemimegalencephaly (HMEG, n=6) and ganglioglioma (GG, n=9) from patients with medically intractable epilepsy and in age-matched controls. "
6.	trans-sodium crocetinate (crocetin)IBA 08/01/2009 - "Balloon cells in FCDIIB and hemimegalencephaly, giant cells in TSC and the astrocytic component of gangliogliomas showed immunoreactivity, colocalizing with conventional GFAP. " 04/01/2023 - "Mutations of mTOR pathway genes are involved in tuberous sclerosis complex (TSC) as well as in a range of cortical malformations from hemimegalencephaly (HME) to type II focal cortical dysplasia (FCD II), leading to the concept of "mTORopathies" (mTOR pathway-related malformations). " 11/01/2021 - "These now question how presurgical evaluation ought to be approached for 'mTORpathies.'Area covered: From review of published primary and secondary articles, the authors summarize evidence to consider focal cortical dysplasia (FCD), tuber sclerosis complex (TSC), and hemimegalencephaly (HME) collectively as MCD mTORpathies. " 01/01/2021 - "These include tuberous sclerosis complex (TSC), hemimegalencephaly (HME), and some types of focal cortical dysplasia (FCD). " 01/01/2020 - "The tuberous sclerosis complex (TSC), focal cortical dysplasia IIB (FCD IIB), and hemimegalencephaly (HME) exhibit similar molecular features that are dependent on the hyperactivation of the mTOR pathway. "
7.	TOR Serine-Threonine KinasesIBA 08/01/2022 - "Hemimegalencephaly is part of a spectrum of disorders, increasingly referred to as mTORopathies, which arise as a result of dysregulation or hyperactivation of the mammalian target of rapamycin (mTOR)-signaling cascade resulting in less restricted cell growth and survival. " 01/01/2019 - "For example, somatic mosaic mutations that activate mammalian target of rapamycin signaling in cortical progenitor cells during development are now recognized as the cause of hemimegalencephaly and some types of focal cortical dysplasia. " 06/01/2015 - "Some focal cortical dysplasia subtypes show a link to the mammalian target of rapamycin signaling cascade; this has now extended to other cortical malformations, including hemimegalencephaly." 04/01/2015 - "Mammalian target of rapamycin pathway mutations cause hemimegalencephaly and focal cortical dysplasia." 11/01/2019 - "Germline and somatic mutation in genes belonging to the Mammalian Target of Rapamycin (mTOR) pathway has been identified in patients suffering from epilepsy secondary to Hemimegalencephaly and focal cortical dysplasia. "
8.	Sirolimus (Rapamycin)FDA Link 01/01/2019 - "Several mosaic mutations of the mammalian/mechanistic target of rapamycin (mTOR) have recently been found in patients with cortical malformations, such as hemimegalencephaly (HME) and focal cortical dysplasia (FCD). " 01/01/2018 - "Over the last decade, there has been increasing evidence that hyperactivation of the mechanistic target of rapamycin (mTOR) pathway is a hallmark of malformations of cortical development such as focal cortical dysplasia (FCD) or hemimegalencephaly. " 02/01/2018 - "It has recently been demonstrated that alterations affecting the mechanistic target of rapamycin (mTOR) signaling pathway result in diverse abnormalities such as dysplastic megalencephaly, hemimegalencephaly, ganglioglioma, dysplastic cerebellar gangliocytoma, focal cortical dysplasia type IIb, and brain lesions associated with tuberous sclerosis. " 05/01/2017 - "The activation of phosphatidylinositol 3-kinase-AKTs-mammalian target of rapamycin cell signaling pathway leads to cell overgrowth and abnormal migration and results in various types of cortical malformations, such as hemimegalencephaly (HME), focal cortical dysplasia, and tuberous sclerosis complex. "
9.	Proteins (Proteins, Gene)FDA Link 01/01/2022 - "Histology revealed increased phosphorylation of ribosomal S6 protein within the unilateral cortex, increased neuronal size, microglia activation and hemispheric enlargement (hemimegalencephaly)." 11/01/2019 - "Mutations in single genes encoding mTOR pathway regulatory proteins have been linked to MCD such as focal cortical dysplasia (FCD) types IIa and IIb, hemimegalencephaly (HME), and megalencephaly. " 09/01/2007 - "Co-expression of cyclin D1 and phosphorylated ribosomal S6 proteins in hemimegalencephaly." 04/01/2005 - "My laboratory recently demonstrated that there is selective expression of phosphoribosomal S6 protein in balloon cells in focal cortical dysplasia and hemimegalencephaly but no expression of the upstream kinase, phospho-p70S6 kinase. "
10.	beta CateninIBA 07/01/2005 - "Targeted gene expression analysis in hemimegalencephaly: activation of beta-catenin signaling." 04/01/2005 - "Enhanced activation of phospho-S6 and beta-catenin suggests two converging cell pathways that can be pivotal in the pathogenesis of focal cortical dysplasia and hemimegalencephaly." 04/01/2005 - "Enhanced transcription of cyclin D1 and c-myc messenger RNAs, increased transcriptionally active beta-catenin, and decreased Ser33/Ser37/Thr41 phospho-beta-catenin suggest activation of the Wnt-1/beta-catenin cascade in hemimegalencephaly, which can lead to aberrant cell proliferation and hemispheric enlargement during brain development. " 04/01/2005 - "Reduced levels of Ser33, Ser37, and Thr41 phospho-beta-catenin, sites known to be phosphorylated by glycogen synthase kinase 3 and to be essential for beta-catenin inactivation, were detected in hemimegalencephaly. "

Therapies and Procedures

1.	Hemispherectomy 04/01/1991 - "Hemimegalencephaly (HME) is a severe unilateral brain malformation the prognosis of which may be improved by hemispherectomy. " 12/01/2021 - "Functional cognitive and language outcomes after cerebral hemispherectomy for hemimegalencephaly." 01/01/2020 - "Minimizing blood loss in hemispherectomy for hemimegalencephaly in low-weight infants: technical note." 01/01/2018 - "Hemimegalencephaly: Seizure Outcome in an Infant after Hemispherectomy." 11/01/2004 - "Diffusion property following functional hemispherectomy in hemimegalencephaly."
2.	Therapeutics 11/01/1997 - "Although white matter abnormalities in the unaffected hemisphere have been reported in hemimegalencephaly, bilateral cortical abnormalities, not reported previously in patients with hemimegalencephaly, may account for the varied clinical outcome with medical therapy or after hemispherectomy." 11/13/2023 - "In this report, the authors present a 6-month-old female with sagittal craniosynostosis, hemimegalencephaly, and intractable epilepsy who underwent a left hemispherotomy with open sagittal synostosis correction followed by cranial molding orthosis therapy. " 03/01/1991 - "Hemimegalencephaly can be recognised on cranial ultrasonography, and the seizures may respond to benzodiazepine therapy." 05/20/2004 - "Surgical solution nowadays became an essential treatment in medial temporal epilepsy, if hippocampal sclerosis or other lesion is present, in therapy resistant lesional extratemporal epilepsies and in catastrophic childhood epilepsies if the epileptic disorder is restricted to one hemisphere (Rasmussen syndrome, hemimegalencephaly, Sturge-Weber disease and posttraumatic or postencephalitic hemispherial epilepsies). "
3.	Ventriculoperitoneal Shunt 01/01/2017 - "Delayed diagnosis of shunt overdrainage following functional hemispherotomy and ventriculoperitoneal shunt placement in a hemimegalencephaly patient." 09/01/2000 - "Ventriculo-peritoneal shunt was placed in 3 children with hemimegalencephaly. " 01/01/2017 - "Here we present a 3-year-old boy with drug-resistant focal onset seizures due to hemimegalencephaly who previously underwent functional hemispherotomy followed by ventriculoperitoneal shunt placement for postoperative hydrocephalus. "
4.	Operative Surgical Procedures 01/01/2015 - "Here we report a method to automatically localize neurons in a sample of human brain removed during a surgical procedure for the treatments of drug resistant epilepsy in a child with hemimegalencephaly, whose neurons and neurites were fluorescence labelled and finally imaged using the two-photon fluorescence microscope. " 11/01/2019 - "We present here a patient suffering from severe neonatal Epilepsy since 3 h of life secondary to Hemimegalencephaly, requiring an anatomic hemispherectomy surgical procedure for seizure control, where by means of next-generation sequencing at an ultra-high depth coverage, we were able to identify a novel somatic mutation in the RHEB gene (NM_005614: c.119A > T: p. "
5.	Vagus Nerve Stimulation 07/01/2015 - "We present an exceptional case of a patient with hemimegalencephaly and secondary intractable epilepsy treated with vagus nerve stimulation (VNS) and subsequent glioblastoma development in the hemimegalencephalic hemisphere 6 years after surgery. "