Abstract |
Low-grade glioneuronal lesions involving tumors such as gangliogliomas and focal cortical dysplasias (FCD) predispose individuals to pharmacoresistant epilepsy. A frequent variant of FCD is composed of dysplastic cytomegalic neurons and Taylor-type balloon cells (FCD(IIb)). Those are similar to cellular elements, which are present in cortical tubers in the autosomal dominant inherited tuberous sclerosis complex ( TSC). This phacomatosis is caused by mutations in the TSC1 or TSC2 genes. Recent data have indicated accumulation of distinct allelic variants of TSC1 also in FCD(IIb). TSC1 represents a key factor in the phosphatidylinositol 3-kinase (PI3K) pathway. A variety of alterations in the PI3K-pathway have been recently reported in epilepsy-associated glioneuronal malformations. Here, we discuss pathogenetic similarities and differences between cortical dysplasias as well epilepsy-associated glioneuronal tumors and TSC-associated cortical tubers with a focus on PI3K-pathway components including ezrin, radixin and moesin (ERM), which represent downstream effectors involved in cytoskeleton-membrane interference. No evidence has been found for mutational events of ERM genes to play a major pathogenetic role in epilepsy-associated glioneuronal malformations. In contrast, aberrant expression of ERM proteins in FCDs and gangliogliomas was observed. These alterations may relate to compromised interactions of dysplastic cellular components in epilepsy-associated glioneuronal lesions and be involved in aberrant PI3K-pathway signaling in epilepsy-associated malformations. However, the underlying cause of PI3K-pathway activation and the functional relationship of PI3K-pathway activity to generation of seizures in epilepsy-associated glioneuronal lesions will need to be determined in the future.
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Authors | Volker Schick, Michael Majores, Arend Koch, Christian E Elger, Johannes Schramm, Horst Urbach, Albert J Becker |
Journal | Epilepsia
(Epilepsia)
Vol. 48 Suppl 5
Pg. 65-73
( 2007)
ISSN: 0013-9580 [Print] United States |
PMID | 17910583
(Publication Type: Journal Article, Research Support, Non-U.S. Gov't, Review)
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Chemical References |
- Cytoskeletal Proteins
- Insulin
- Membrane Proteins
- Microfilament Proteins
- TSC1 protein, human
- Tuberous Sclerosis Complex 1 Protein
- Tumor Suppressor Proteins
- ezrin
- moesin
- radixin
- Phosphatidylinositol 3-Kinases
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Topics |
- Animals
- Brain Diseases
(enzymology, metabolism, pathology)
- Brain Neoplasms
(enzymology)
- Cerebral Cortex
(abnormalities, metabolism, pathology)
- Cytoskeletal Proteins
(metabolism)
- Epilepsies, Partial
(enzymology, metabolism, pathology)
- Ganglioglioma
(enzymology, metabolism, pathology)
- Humans
- Insulin
(physiology)
- Membrane Proteins
(metabolism)
- Microfilament Proteins
(metabolism)
- Neurons
(enzymology, metabolism, pathology)
- Phosphatidylinositol 3-Kinases
(metabolism, physiology)
- Signal Transduction
(physiology)
- Tuberous Sclerosis
(enzymology, pathology)
- Tuberous Sclerosis Complex 1 Protein
- Tumor Suppressor Proteins
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