Evidence map›Paper›PMID 41489401›Full record

ArticleEpilepsia2026

Memantine treatment in individuals with GRIN gain-of-function variants is associated with improvements in behavior, development, and seizure frequency.

Maike Karnstedt, Riley E Perszyk, Scott J Myers, Ellington McDaniels, Marta Somorai, Ingo Borggraefe, Danielle C M Veenma, An-Sofie Schoonjans, Pasquale Striano, Tadeu A Fantaneanu and 8 more

Abstract read
In one paragraph

Article in Epilepsia, 2026. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 1 paper.

0numbers the graph read from it
0cells of the map it votes in
1citing 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

1 citing paper in PubMed.

  1. 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

18 authors.

Maike KarnstedtInstitute of Human Genetics, University of Leipzig Medical Center, Leipzig, Germany.ORCID https://orcid.org/0009-0009-0619-7493
Riley E PerszykDepartment of Pharmacology and Chemical Biology, Emory University School of Medicine, Atlanta, Georgia, USA.ORCID https://orcid.org/0000-0001-8283-7709
Scott J MyersDepartment of Pharmacology and Chemical Biology, Emory University School of Medicine, Atlanta, Georgia, USA.ORCID https://orcid.org/0000-0002-6689-3978
Ellington McDanielsDepartment of Pharmacology and Chemical Biology, Emory University School of Medicine, Atlanta, Georgia, USA.
Marta SomoraiCenter for Rare Developmental Disorders, Technical University of Munich, kbo Children's Center Munich, Munich, Germany.ORCID https://orcid.org/0009-0002-1171-3965
Ingo BorggraefeDivision of Pediatric Neurology, Developmental Medicine, and Social Pediatrics, Department of Pediatrics, University Hospital Munich, Munich, Germany.ORCID https://orcid.org/0000-0002-8484-5945
Danielle C M VeenmaDepartment of Pediatrics, Erasmus MC Sophia Children's Hospital, Rotterdam, the Netherlands.ORCID https://orcid.org/0000-0001-6468-6521
An-Sofie SchoonjansDepartment of Pediatric Neurology, Antwerp University Hospital, Edegem, Belgium.ORCID https://orcid.org/0000-0001-7545-518X
Pasquale StrianoDepartment of Neurosciences, Rehabilitation, Ophthalmology, Genetics, Maternal and Child Health, University of Genoa, Genoa, Italy.ORCID https://orcid.org/0009-0006-9686-6678
Tadeu A FantaneanuDepartment of Medicine, Ottawa Hospital, Ottawa Hospital Research Institute, University of Ottawa, Ottawa, Ontario, Canada.ORCID https://orcid.org/0000-0003-4218-068X
Steffen SyrbeDivision of Pediatric Epileptology, Center for Pediatrics and Adolescent Medicine, University Hospital Heidelberg, Heidelberg, Germany.ORCID https://orcid.org/0000-0003-2543-4844
Kristen ParkDepartments of Pediatrics, Pharmacology, Neurology, and Otolaryngology, School of Medicine and Children's Hospital Colorado, University of Colorado, Boulder, Colorado, USA.ORCID https://orcid.org/0000-0001-5527-3047
Wenjuan ChenDepartment of Pharmacology and Chemical Biology, Emory University School of Medicine, Atlanta, Georgia, USA.
Hongjie YuanDepartment of Pharmacology and Chemical Biology, Emory University School of Medicine, Atlanta, Georgia, USA.ORCID https://orcid.org/0000-0002-8127-7145
Stephen F TraynelisDepartment of Pharmacology and Chemical Biology, Emory University School of Medicine, Atlanta, Georgia, USA.ORCID https://orcid.org/0000-0002-3750-9615
Timothy A BenkeDepartments of Pediatrics, Pharmacology, Neurology, and Otolaryngology, School of Medicine and Children's Hospital Colorado, University of Colorado, Boulder, Colorado, USA.ORCID https://orcid.org/0000-0002-6969-5061
Johannes R LemkeInstitute of Human Genetics, University of Leipzig Medical Center, Leipzig, Germany.ORCID https://orcid.org/0000-0002-4435-6610
Ilona KreyInstitute of Human Genetics, University of Leipzig Medical Center, Leipzig, Germany.ORCID https://orcid.org/0000-0002-9168-7615

Funding

Georgia CTSA NIH award UL1-TR002378GRIN2B FoundationNIH-NICHD HD082373NIH-NINDS NS111619Simons Foundation SFARI 732132
6 · The paper itself

Abstract

objectiveGRIN-related disorders due to pathogenic variants in GRIN1, GRIN2A, GRIN2B, or GRIN2D genes are associated with altered N-methyl-D-aspartate receptor (NMDAR) function. Functional changes include gain (GoF) and loss of receptor function (LoF). Clinical reports describing the use of the NMDAR blocker memantine in GRIN-related disorders show a diverse and inconsistent spectrum of treatment responses.

methodsTo evaluate clinical responses to memantine, we collected retrospective data on 34 individuals with GRIN variants, including 20 unpublished and 14 published cases. Variants were reclassified following American College of Medical Genetics and Genomics guidelines, and six in vitro functional assays were used to assess receptor function. We compared individuals with pathogenic GoF versus LoF in terms of associated clinical improvements, memantine sensitivity, and variant localization within the gene.

resultsIn 19 of the 34 variants, a pathogenic likely or possible GoF of the receptor was detected. Fourteen of 19 individuals (74%) benefited from memantine, comprising improvements in behavior (71%), development (50%), and seizure frequency (39%). Individuals with either LoF or a functionally indeterminate or no effect GRIN variant (15/34 individuals) showed significantly less benefit from memantine treatment but nevertheless rare adverse events (3/15). An increased distance of the variant from the memantine binding site was associated with a clinical benefit. SIGNIFICANCE: Our retrospective observational study outlines the importance of correct classification of GRIN variants with regard to pathogenicity and functional consequence prior to applying memantine or other precision medicine approaches in clinical trials. Furthermore, the distance from a GoF variant to the memantine binding site correlated with a positive treatment response and may, at least in part, explain different degrees of therapeutic benefit.

Indexed as

Excitatory Amino Acid AntagonistsGain of Function MutationMemantineNerve Tissue ProteinsReceptors, N-Methyl-D-AspartateSeizuresAdolescentAdultChildChild, PreschoolFemaleHumansMaleMiddle AgedRetrospective StudiesTreatment OutcomeExcitatory Amino Acid AntagonistsGRIN1 protein, humanMemantineNerve Tissue ProteinsReceptors, N-Methyl-D-Aspartatedevelopmental and epileptic encephalopathyepilepsyprecision medicineretrospective observational case seriestargeted treatment

Identifiers

PMID41489401
PMCPMC13075606

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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.