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01-12-2019 | Epilepsy | Original Paper

Precise detection of low-level somatic mutation in resected epilepsy brain tissue

Authors: Nam Suk Sim, Ara Ko, Woo Kyeong Kim, Se Hoon Kim, Ju Seong Kim, Kyu-Won Shim, Eleonora Aronica, Caroline Mijnsbergen, Wim G. M. Spliet, Hyun Yong Koh, Heung Dong Kim, Joon Soo Lee, Dong Seok Kim, Hoon-Chul Kang, Jeong Ho Lee

Published in: Acta Neuropathologica | Issue 6/2019

Abstract

Low-level somatic mutations have been shown to be the major genetic etiology of intractable epilepsy. The extents thereof, however, have yet to be systematically and accurately explored in a large cohort of resected epilepsy brain tissues. Moreover, clinically useful and precise analysis tools for detecting low-level somatic mutations from unmatched formalin-fixed paraffin-embedded (FFPE) brain samples, the most clinically relevant samples, are still lacking. In total, 446 tissues samples from 232 intractable epilepsy patients with various brain pathologies were analyzed using deep sequencing (average read depth, 1112x) of known epilepsy-related genes (up to 28 genes) followed by confirmatory site-specific amplicon sequencing. Pathogenic mutations were discovered in 31.9% (74 of 232) of the resected epilepsy brain tissues and were recurrently found in only eight major focal epilepsy genes, including AKT3, DEPDC5, MTOR, PIK3CA, TSC1, TSC2, SCL35A2, and BRAF. Somatic mutations, two-hit mutations, and germline mutations accounted for 22.0% (51), 0.9% (2), and 9.1% (21) of the patients with intractable epilepsy, respectively. The majority of pathogenic somatic mutations (62.3%, 33 of 53) had a low variant allelic frequency of less than 5%. The use of deep sequencing replicates in the eight major focal epilepsy genes robustly increased PPVs to 50–100% and sensitivities to 71–100%. In an independent FCDII cohort of only unmatched FFPE brain tissues, deep sequencing replicates in the eight major focal epilepsy genes identified pathogenic somatic mutations in 33.3% (5 of 15) of FCDII individuals (similar to the genetic detecting rate in the entire FCDII cohort) without any false-positive calls. Deep sequencing replicates of major focal epilepsy genes in unmatched FFPE brain tissues can be used to accurately and efficiently detect low-level somatic mutations, thereby improving overall patient care by enriching genetic counseling and informing treatment decisions.

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Title: Precise detection of low-level somatic mutation in resected epilepsy brain tissue
Authors: Nam Suk Sim
Ara Ko
Woo Kyeong Kim
Se Hoon Kim
Ju Seong Kim
Kyu-Won Shim
Eleonora Aronica
Caroline Mijnsbergen
Wim G. M. Spliet
Hyun Yong Koh
Heung Dong Kim
Joon Soo Lee
Dong Seok Kim
Hoon-Chul Kang
Jeong Ho Lee
Publication date: 01-12-2019
Publisher: Springer Berlin Heidelberg
Keyword: Epilepsy
Published in: Acta Neuropathologica / Issue 6/2019
Print ISSN: 0001-6322
Electronic ISSN: 1432-0533
DOI: https://doi.org/10.1007/s00401-019-02052-6

Keynote webinar | Spotlight on medication adherence

Springer Medicine

Precise detection of low-level somatic mutation in resected epilepsy brain tissue

Abstract

Keynote webinar | Spotlight on medication adherence

Springer Medicine

Abstract

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