Epilepsy phenotype in individuals with chromosomal duplication encompassing FGF12

Marjolein H. Willemsen, Himanshu Goel, Judith S. Verhoeven, Hilde M.H. Braakman, Nicole de Leeuw, Alison Freeth, Berge A. Minassian

Research output: Contribution to journalArticle

Abstract

Intragenic mutations in FGF12 are associated with intractable seizures, developmental regression, intellectual disability, ataxia, hypotonia, and feeding difficulties. FGF12 duplications are rarely reported, but it was suggested that those might have a similar gain-of-function effect and lead to a more or less comparable phenotype. A favorable response to the sodium blocker phenytoin was reported in several cases, both in patients with an intragenic mutation and in patients with a duplication of FGF12. We report three individuals from two families with FGF12 duplications. The duplications are flanked and probably mediated by two long interspersed nuclear elements (LINEs). The duplication cases show phenotypic overlap with the cases with intragenic mutations. Though the onset of epilepsy might be later, after the onset of seizures both groups show developmental stagnation and regression in several cases. This illustrates and further confirms that chromosomal FGF12 duplications and intragenic gain-of-function mutations yield overlapping phenotypes.

Original languageEnglish (US)
Pages (from-to)301-306
Number of pages6
JournalEpilepsia Open
Volume5
Issue number2
DOIs
StatePublished - Jun 1 2020

Keywords

  • FGF12
  • LINE
  • developmental regression
  • epilepsy
  • intellectual disability
  • microduplication 3q28q29

ASJC Scopus subject areas

  • Neurology
  • Clinical Neurology

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    Willemsen, M. H., Goel, H., Verhoeven, J. S., Braakman, H. M. H., de Leeuw, N., Freeth, A., & Minassian, B. A. (2020). Epilepsy phenotype in individuals with chromosomal duplication encompassing FGF12. Epilepsia Open, 5(2), 301-306. https://doi.org/10.1002/epi4.12396