Evidence map›Paper›PMID 39751777›Full record

ArticleEpilepsia2025

Detecting somatic variants in purified brain DNA obtained from surgically implanted depth electrodes in epilepsy.

Rumika Mascarenhas, Daria Merrikh, Maryam Khanbabaei, Navprabhjot Kaur, Navid Ghaderi, Tatiana Maroilley, Yiping Liu, Tyler Soule, Juan Pablo Appendino, Julia Jacobs and 6 more

Abstract read
In one paragraph

Article in Epilepsia, 2025. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 3 papers.

0numbers the graph read from it
0cells of the map it votes in
3citing papers in PubMed
–field-weighted citation impact
1 · What the graph read from it

What it found

Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.

The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.

2 · The registry

The trial behind it

Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.

Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.

3 · Its place in the literature

Who cites it

3 citing papers in PubMed.

  1. Review
  2. Article
  3. Review
4 · The record

Corrections and comments

PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.

5 · Who and what money

Authors and funding

16 authors.

Rumika MascarenhasDepartment of Clinical Neurosciences, University of Calgary, Calgary, Alberta, Canada.
Daria MerrikhDepartment of Clinical Neurosciences, University of Calgary, Calgary, Alberta, Canada.
Maryam KhanbabaeiDepartment of Clinical Neurosciences, University of Calgary, Calgary, Alberta, Canada.
Navprabhjot KaurDepartment of Clinical Neurosciences, University of Calgary, Calgary, Alberta, Canada.
Navid GhaderiDepartment of Clinical Neurosciences, University of Calgary, Calgary, Alberta, Canada.
Tatiana MaroilleyAlberta Children's Hospital Research Institute, University of Calgary, Calgary, Alberta, Canada.
Yiping LiuFlow Cytometry Core Facility, University of Calgary, Calgary, Alberta, Canada.
Tyler SouleDepartment of Clinical Neurosciences, University of Calgary, Calgary, Alberta, Canada.
Juan Pablo AppendinoDepartment of Clinical Neurosciences, University of Calgary, Calgary, Alberta, Canada.ORCID https://orcid.org/0000-0002-1112-7002
Julia JacobsDepartment of Clinical Neurosciences, University of Calgary, Calgary, Alberta, Canada.
Samuel WiebeDepartment of Clinical Neurosciences, University of Calgary, Calgary, Alberta, Canada.ORCID https://orcid.org/0000-0002-1061-9099
Calgary Comprehensive Epilepsy Program Collaborators
Walter HaderDepartment of Clinical Neurosciences, University of Calgary, Calgary, Alberta, Canada.
Gerald PfefferDepartment of Clinical Neurosciences, University of Calgary, Calgary, Alberta, Canada.
Maja Tarailo-GraovacAlberta Children's Hospital Research Institute, University of Calgary, Calgary, Alberta, Canada.ORCID https://orcid.org/0000-0002-4472-8584
Karl Martin KleinDepartment of Clinical Neurosciences, University of Calgary, Calgary, Alberta, Canada.ORCID https://orcid.org/0000-0002-6654-1665

Funding

Azrieli FoundationCanada Foundation for Innovation 36624CIHREpilepsy CanadaFondation Brain CanadaHealth CanadaUniversity of Calgary
6 · The paper itself

Abstract

objectiveSomatic variants causing epilepsy are challenging to detect, as they are only present in a subset of brain cells (e.g., mosaic), resulting in low variant allele frequencies. Traditional methods relying on surgically resected brain tissue are limited to patients undergoing brain surgery. We developed an improved protocol to detect somatic variants using DNA from stereoelectroencephalographic (SEEG) depth electrodes, enabling access to a larger patient cohort and diverse brain regions. This protocol mitigates issues of contamination and low yields by purifying neuronal nuclei using fluorescence-activated nuclei sorting (FANS).

methodsSEEG depth electrodes were collected upon extraction from 41 brain regions across 17 patients undergoing SEEG. Nuclei were isolated separately from depth electrodes in the affected brain regions (seizure onset zone) and the unaffected brain regions. Neuronal nuclei were isolated using FANS, and DNA was amplified using primary template amplification. Short tandem repeat (STR) analysis and postsequencing allelic imbalance assessment were used to evaluate sample integrity. High-quality amplified DNA samples from affected brain regions, patient-matched unaffected brain regions, and genomic DNA were subjected to whole exome sequencing (WES). A bioinformatic workflow was developed to reduce false positives and to accurately detect somatic variants in the affected brain region.

resultsBased on DNA yield and STR analysis, 14 SEEG-derived neuronal DNA samples (seven affected and seven unaffected) across seven patients underwent WES. From the variants prioritized using our bioinformatic workflow, we chose four candidate variants in MTOR, CSDE1, KLLN, and NLE1 across four patients based on pathogenicity scores and association with phenotype. All four variants were validated using digital droplet polymerase chain reaction. SIGNIFICANCE: Our approach enhances the reliability and applicability of SEEG-derived DNA for epilepsy, offering insights into its molecular basis, facilitating epileptogenic zone identification, and advancing precision medicine.

Indexed as

BrainDNAElectrodes, ImplantedEpilepsyGenetic VariationAdolescentAdultChildElectroencephalographyExome SequencingFemaleHumansMaleMiddle AgedYoung AdultDNAdepth electrodesDNAepilepsysomatic variantstereo‐EEG

Identifiers

PMID39751777
PMCPMC11997914

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LicenceCC BY-NC-ND
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Registered trials

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Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.