Genetic and Electrophysiologic Study in Focal Drug-resistant Epilepsies

Brain somatic mutations are increasingly recognized as a major cause of focal epilepsies. These include mTOR pathway mutations underlying cortical malformations such as focal cortical dysplasia and hemimegalencephaly, and SLC35A2 mutations in MOGHE, and activating variants in the SHH pathway in hypothalamic hamartomas. This study aims to identify brain somatic mutations using paired blood-brain samples and trace DNA from stereo-EEG electrodes, and to perform functional validation of candidate variants in children with drug-resistant focal epilepsy.

Sex

All

Minimum age

3 Months

Maximum age

25 Years

Inclusion Criteria:

* Children with focal drug-resistant epilepsy including Focal Cortical Dysplasia, Hemimegalencephaly, Tuberous Sclerosis, Mild malformation of cortical development with oligodendroglial hyperplasia in epilepsy (MOGHE), Hypothalamic Hamartomas, Sturge-Weber syndrome, Rasmussen encephalitis, gliomas
* Their parents who have signed informed consent 1) for their child's participation (for parents) and 2) for themselves
* Social security coverage or foreign regime recognized in France

Exclusion Criteria:

* refusal to participate in the study
* contraindication to anaesthesia, to MRI or to surgery
* no medical insurance coverage

• RESULTBaldassari S, Ribierre T, Marsan E, Adle-Biassette H, Ferrand-Sorbets S, Bulteau C, Dorison N, Fohlen M, Polivka M, Weckhuysen S, Dorfmuller G, Chipaux M, Baulac S. Dissecting the genetic basis of focal cortical dysplasia: a large cohort study. Acta Neuropathol. 2019 Dec;138(6):885-900. doi: 10.1007/s00401-019-02061-5. Epub 2019 Aug 23. PMID 31444548
• RESULTBonduelle T, Hartlieb T, Baldassari S, Sim NS, Kim SH, Kang HC, Kobow K, Coras R, Chipaux M, Dorfmuller G, Adle-Biassette H, Aronica E, Lee JH, Blumcke I, Baulac S. Frequent SLC35A2 brain mosaicism in mild malformation of cortical development with oligodendroglial hyperplasia in epilepsy (MOGHE). Acta Neuropathol Commun. 2021 Jan 6;9(1):3. doi: 10.1186/s40478-020-01085-3. PMID 33407896
• RESULTLee WS, Baldassari S, Chipaux M, Adle-Biassette H, Stephenson SEM, Maixner W, Harvey AS, Lockhart PJ, Baulac S, Leventer RJ. Gradient of brain mosaic RHEB variants causes a continuum of cortical dysplasia. Ann Clin Transl Neurol. 2021 Feb;8(2):485-490. doi: 10.1002/acn3.51286. Epub 2021 Jan 12. PMID 33434304
• RESULTKim S, Baldassari S, Sim NS, Chipaux M, Dorfmuller G, Kim DS, Chang WS, Taly V, Lee JH, Baulac S. Detection of Brain Somatic Mutations in Cerebrospinal Fluid from Refractory Epilepsy Patients. Ann Neurol. 2021 Jun;89(6):1248-1252. doi: 10.1002/ana.26080. Epub 2021 Apr 20. PMID 33834539
• RESULTBarba C, Blumcke I, Winawer MR, Hartlieb T, Kang HC, Grisotto L, Chipaux M, Bien CG, Hermanovska B, Porter BE, Lidov HGW, Cetica V, Woermann FG, Lopez-Rivera JA, Canoll PD, Mader I, D'Incerti L, Baldassari S, Yang E, Gaballa A, Vogel H, Straka B, Macconi L, Polster T, Grant GA, Krskova L, Shin HJ, Ko A, Crino PB, Krsek P, Lee JH, Lal D, Baulac S, Poduri A, Guerrini R; SLC35A2 Study Group. Clinical Features, Neuropathology, and Surgical Outcome in Patients With Refractory Epilepsy and Brain Somatic Variants in the SLC35A2 Gene. Neurology. 2023 Jan 31;100(5):e528-e542. doi: 10.1212/WNL.0000000000201471. Epub 2022 Oct 28. PMID 36307217