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Seizure Apr 2020Designed from the 60s to the 80s for adults, and despite the development of many new techniques, invasive explorations still have indications in children with focal... (Review)
Review
Designed from the 60s to the 80s for adults, and despite the development of many new techniques, invasive explorations still have indications in children with focal drug-resistant epilepsy. The main types are stereoelectroencephalography (SEEG) and subdural explorations (SDE). They provide precise information on the localization of the epileptogenic zone (EZ), its relationships with eloquent cortex, and the feasibility of performing a tailored surgical resection. Thermocoagulations, which are a diagnostic and therapeutic tool, can be performed using SEEG electrodes. Both techniques are feasible in children, with an age limitation for SEEG (which requires a bone thickness above 2 mm). The complication rate is higher with SDE. Opposed for a long time and never compared in a systematic study, they should presently be considered complementary. The indications cannot be directly inferred from those for adults, as there are pediatric particularities in the seizures' semiology, functional areas, imaging and urgent situations. We successively discuss the choice in individual cases of SEEG or SDE respectively, the specific problematic in infancy and early childhood, the schema in SEEG for cryptogenic epilepsies (in particular insular), the particularities of polymicrogyria and deeply located lesions, and finally, SEEG designed for thermocoagulations. Future improvements should include more accurate implantation schemas thanks to advanced non-invasive explorations and possibilities to perform SEEG in infants.
Topics: Adolescent; Child; Child, Preschool; Drug Resistant Epilepsy; Electrocoagulation; Electrocorticography; Epilepsies, Partial; Humans; Stereotaxic Techniques
PubMed: 30503504
DOI: 10.1016/j.seizure.2018.11.008 -
Orphanet Journal of Rare Diseases Mar 2024Pallister-Killian syndrome (PKS) is a rare genetic disorder caused by mosaic tetrasomy of 12p with wide neurological involvement. Intellectual disability, developmental... (Review)
Review
BACKGROUND
Pallister-Killian syndrome (PKS) is a rare genetic disorder caused by mosaic tetrasomy of 12p with wide neurological involvement. Intellectual disability, developmental delay, behavioral problems, epilepsy, sleep disturbances, and brain malformations have been described in most individuals, with a broad phenotypic spectrum. This observational study, conducted through brain MRI scan analysis on a cohort of patients with genetically confirmed PKS, aims to systematically investigate the neuroradiological features of this syndrome and identify the possible existence of a typical pattern. Moreover, a literature review differentiating the different types of neuroimaging data was conducted for comparison with our population.
RESULTS
Thirty-one individuals were enrolled (17 females/14 males; age range 0.1-17.5 years old at first MRI). An experienced pediatric neuroradiologist reviewed brain MRIs, blindly to clinical data. Brain abnormalities were observed in all but one individual (compared to the 34% frequency found in the literature review). Corpus callosum abnormalities were found in 20/30 (67%) patients: 6 had callosal hypoplasia; 8 had global hypoplasia with hypoplastic splenium; 4 had only hypoplastic splenium; and 2 had a thin corpus callosum. Cerebral hypoplasia/atrophy was found in 23/31 (74%) and ventriculomegaly in 20/31 (65%). Other frequent features were the enlargement of the cisterna magna in 15/30 (50%) and polymicrogyria in 14/29 (48%). Conversely, the frequency of the latter was found to be 4% from the literature review. Notably, in our population, polymicrogyria was in the perisylvian area in all 14 cases, and it was bilateral in 10/14.
CONCLUSIONS
Brain abnormalities are very common in PKS and occur much more frequently than previously reported. Bilateral perisylvian polymicrogyria was a main aspect of our population. Our findings provide an additional tool for early diagnosis.Further studies to investigate the possible correlations with both genotype and phenotype may help to define the etiopathogenesis of the neurologic phenotype of this syndrome.
Topics: Male; Female; Humans; Child; Infant; Child, Preschool; Adolescent; Polymicrogyria; Chromosome Disorders; Neuroimaging; Brain; Brain Diseases; Chromosomes, Human, Pair 12; Observational Studies as Topic
PubMed: 38459574
DOI: 10.1186/s13023-024-03065-5 -
Developmental Medicine and Child... Oct 2019We aimed to systematically review the speech production, language, and oral function phenotype of bilateral perisylvian polymicrogyria (BPP), and examine the correlation...
AIM
We aimed to systematically review the speech production, language, and oral function phenotype of bilateral perisylvian polymicrogyria (BPP), and examine the correlation between the topography of polymicrogyria and the severity of speech, language, and oral functional impairment.
METHOD
A systematic search of MEDLINE, Embase, and PubMed databases was completed on 26th October 2017 using Medical Subject Heading terms synonymous with BPP and speech, language, or oral motor impairment. In total, 2411 papers were identified and 48 met inclusion criteria.
RESULTS
Expressive and receptive language impairment and oral structural and functional deficits are frequent in BPP. Expressive deficits are frequently more severe than receptive. Only one study used formal assessments to demonstrate the presence of speech disorder, namely dysarthria. Seven studies reported an association between diffuse BPP and more severe language impairment.
INTERPRETATION
Findings confirmed that language deficits are common in BPP, though assessment of the specific speech phenotype is limited. The paucity of high quality studies detailing the specific communication phenotype of BPP highlights the need for further investigation. Improving understanding of this phenotype will inform the development of targeted therapies and lead to better long-term outcomes.
WHAT THIS PAPER ADDS
Speech, language, and oral functional impairments are common in individuals with bilateral perisylvian polymicrogyria. Posterior polymicrogyria is associated with a less severe language impairment than anterior polymicrogyria. Deeper investigation of speech is needed to understand implicated networks in this malformation.
Topics: Abnormalities, Multiple; Humans; Intellectual Disability; Language; Language Development Disorders; Malformations of Cortical Development; Phenotype; Severity of Illness Index; Speech
PubMed: 30680716
DOI: 10.1111/dmcn.14153 -
Frontiers in Genetics 2021Occipital cortical malformation (OCCM) is a disease caused by malformations of cortical development characterized by polymicrogyria and pachygyria of the occipital lobes...
Occipital cortical malformation (OCCM) is a disease caused by malformations of cortical development characterized by polymicrogyria and pachygyria of the occipital lobes and childhood-onset seizures. The recessive or complex heterozygous variants of the gene are identified as the cause of OCCM. In the present study, we identified novel complex heterozygous variants (c.470G > A and c.4030 + 1G > A) of the gene in a Chinese female with childhood-onset seizures. Cranial magnetic resonance imaging was normal. Functional experiments confirmed that both variant sites caused premature truncation of the laminin γ3 chain. Bioinformatics analysis predicted 10 genes interacted with with an interaction score of 0.4 ( value = 1.0e-16). The proteins encoded by these genes were mainly located in the basement membrane and extracellular matrix component. Furthermore, the biological processes and molecular functions from gene ontology analysis indicated that laminin γ3 chain and related proteins played an important role in structural support and cellular processes through protein-containing complex binding and signaling receptor binding. KEGG pathway enrichment predicted that the gene variant was most likely to participate in the occurrence and development of OCCM through extracellular matrix receptor interaction and PI3K-Akt signaling pathway.
PubMed: 34354730
DOI: 10.3389/fgene.2021.616761 -
Biomechanics and Modeling in... Oct 2015The human brain is the continuous subject of extensive investigation aimed at understanding its behavior and function. Despite a clear evidence that mechanical factors... (Review)
Review
The human brain is the continuous subject of extensive investigation aimed at understanding its behavior and function. Despite a clear evidence that mechanical factors play an important role in regulating brain activity, current research efforts focus mainly on the biochemical or electrophysiological activity of the brain. Here, we show that classical mechanical concepts including deformations, stretch, strain, strain rate, pressure, and stress play a crucial role in modulating both brain form and brain function. This opinion piece synthesizes expertise in applied mathematics, solid and fluid mechanics, biomechanics, experimentation, material sciences, neuropathology, and neurosurgery to address today's open questions at the forefront of neuromechanics. We critically review the current literature and discuss challenges related to neurodevelopment, cerebral edema, lissencephaly, polymicrogyria, hydrocephaly, craniectomy, spinal cord injury, tumor growth, traumatic brain injury, and shaken baby syndrome. The multi-disciplinary analysis of these various phenomena and pathologies presents new opportunities and suggests that mechanical modeling is a central tool to bridge the scales by synthesizing information from the molecular via the cellular and tissue all the way to the organ level.
Topics: Animals; Brain; Brain Diseases; Compressive Strength; Computer Simulation; Elastic Modulus; Humans; Intracranial Pressure; Mechanotransduction, Cellular; Models, Neurological; Neurons; Stress, Mechanical; Tensile Strength
PubMed: 25716305
DOI: 10.1007/s10237-015-0662-4 -
Proceedings of the National Academy of... Jan 2023encodes an evolutionarily conserved widely expressed novel 8-pass transmembrane protein of unknown function in human. Here we identify homozygous hypomorphic missense...
encodes an evolutionarily conserved widely expressed novel 8-pass transmembrane protein of unknown function in human. Here we identify homozygous hypomorphic missense variants in our recessive polymicrogyria (PMG) cohort. Patients carrying mutations exhibit striking neocortical PMG and intellectual disability. knockout mice fail to develop midline hemispheric cleavage, whereas knock-in of patient mutations and patient-derived brain organoids show defects in apical cell polarity and radial glial scaffolding. We found that TMEM161B modulates actin filopodia, functioning upstream of the Rho-GTPase CDC42. Our data link with human PMG, likely regulating radial glia apical polarity during neocortical development.
Topics: Animals; Humans; Mice; Ependymoglial Cells; Mice, Knockout; Neocortex
PubMed: 36669109
DOI: 10.1073/pnas.2209983120 -
Journal of Pediatric Neurosciences 2017Encephalocranial lipomatosis is a rare disorder that characteristically involves ectomesodermal tissues such as skin, eye, and the central nervous system. Here, we...
Encephalocranial lipomatosis is a rare disorder that characteristically involves ectomesodermal tissues such as skin, eye, and the central nervous system. Here, we report a 3-year-old girl presented with developmental delay, seizures, limbal dermoid, and weakness of right lower limb. Imaging revealed hemiatrophy, arachnoid cyst, and polymicrogyria. The constellation of clinical finding and imaging leads to the diagnosis.
PubMed: 28553398
DOI: 10.4103/jpn.JPN_130_16 -
AJNR. American Journal of Neuroradiology Jan 2009The purpose of this article was to review the embryologic stages of the cerebral cortex, illustrate the classification of disorders of cortical formation, and finally... (Review)
Review
The purpose of this article was to review the embryologic stages of the cerebral cortex, illustrate the classification of disorders of cortical formation, and finally describe the main MR imaging features of these disorders. Disorders of cortical formation are classified according to the embryologic stage of the cerebral cortex at which the abnormality occurred. MR imaging shows diminished cortical thickness and sulcation in microcephaly, enlarged dysplastic cortex in hemimegalencephaly, and ipsilateral focal cortical thickening with radial hyperintense bands in focal cortical dysplasia. MR imaging detects smooth brain in classic lissencephaly, the nodular cortex with cobblestone cortex with congenital muscular dystrophy, and the ectopic position of the gray matter with heterotopias. MR imaging can detect polymicrogyria and related syndromes as well as the types of schizencephaly. We concluded that MR imaging is essential to demonstrate the morphology, distribution, and extent of different disorders of cortical formation as well as the associated anomalies and related syndromes.
Topics: Brain Diseases; Cerebral Cortex; Humans; Magnetic Resonance Imaging
PubMed: 18687750
DOI: 10.3174/ajnr.A1223 -
Brain : a Journal of Neurology Sep 2022Variants in RAC3, encoding a small GTPase RAC3 which is critical for the regulation of actin cytoskeleton and intracellular signal transduction, are associated with a...
Variants in RAC3, encoding a small GTPase RAC3 which is critical for the regulation of actin cytoskeleton and intracellular signal transduction, are associated with a rare neurodevelopmental disorder with structural brain anomalies and facial dysmorphism. We investigated a cohort of 10 unrelated participants presenting with global psychomotor delay, hypotonia, behavioural disturbances, stereotyped movements, dysmorphic features, seizures and musculoskeletal abnormalities. MRI of brain revealed a complex pattern of variable brain malformations, including callosal abnormalities, white matter thinning, grey matter heterotopia, polymicrogyria/dysgyria, brainstem anomalies and cerebellar dysplasia. These patients harboured eight distinct de novo RAC3 variants, including six novel variants (NM_005052.3): c.34G > C p.G12R, c.179G > A p.G60D, c.186_188delGGA p.E62del, c.187G > A p.D63N, c.191A > G p.Y64C and c.348G > C p.K116N. We then examined the pathophysiological significance of these novel and previously reported pathogenic variants p.P29L, p.P34R, p.A59G, p.Q61L and p.E62K. In vitro analyses revealed that all tested RAC3 variants were biochemically and biologically active to variable extent, and exhibited a spectrum of different affinities to downstream effectors including p21-activated kinase 1. We then focused on the four variants p.Q61L, p.E62del, p.D63N and p.Y64C in the Switch II region, which is essential for the biochemical activity of small GTPases and also a variation hot spot common to other Rho family genes, RAC1 and CDC42. Acute expression of the four variants in embryonic mouse brain using in utero electroporation caused defects in cortical neuron morphology and migration ending up with cluster formation during corticogenesis. Notably, defective migration by p.E62del, p.D63N and p.Y64C were rescued by a dominant negative version of p21-activated kinase 1. Our results indicate that RAC3 variants result in morphological and functional defects in cortical neurons during brain development through variant-specific mechanisms, eventually leading to heterogeneous neurodevelopmental phenotypes.
Topics: Animals; Humans; Mice; Neurodevelopmental Disorders; Neurons; Phenotype; p21-Activated Kinases; rac GTP-Binding Proteins
PubMed: 35851598
DOI: 10.1093/brain/awac106 -
Brain Communications 2021Polymicrogyria is a malformation of cortical development characterized by overfolding and abnormal lamination of the cerebral cortex. Manifestations include epilepsy,...
Polymicrogyria is a malformation of cortical development characterized by overfolding and abnormal lamination of the cerebral cortex. Manifestations include epilepsy, speech disturbance and motor and cognitive disability. Causes include acquired prenatal insults and inherited and genetic variants. The proportion of patients with polymicrogyria and a causative germline or mosaic variant is not known. The aim of this study was to identify the monogenic causes of polymicrogyria in a heterogeneous cohort of patients reflective of specialized referral services. Patients with polymicrogyria were recruited from two clinical centres in Australia and Belgium. Patients with evidence of congenital cytomegalovirus infection or causative chromosomal copy number variants were excluded. One hundred and twenty-three patients were tested using deep sequencing gene panels including known and candidate genes for malformations of cortical development. Causative and potentially causative variants were identified and correlated with phenotypic features. Pathogenic or likely pathogenic variants were identified in 25/123 (20.3%) patients. A candidate variant was identified for an additional patient but could not be confirmed as , and therefore it was classified as being of uncertain significance with high clinical relevance. Of the 22 dominant variants identified, 5 were mosaic with allele fractions less than 0.33 and the lowest allele fraction 0.09. The most common causative genes were and . The other eleven causative genes were , , and . A genetic cause was more likely to be identified in the presence of an abnormal head size or additional brain malformations suggestive of a tubulinopathy, such as dysmorphic basal ganglia. A gene panel test provides greater sequencing depth and sensitivity for mosaic variants than whole exome or genome sequencing but is limited to the genes included, potentially missing variants in newly discovered genes. The diagnostic yield of 20.3% indicates that polymicrogyria may be associated with genes not yet known to be associated with brain malformations, brain-specific somatic mutations or non-genetic causes.
PubMed: 33604570
DOI: 10.1093/braincomms/fcaa221