Mosaic SCN1A mutation in familial severe myoclonic epilepsy of infancy

Carla Marini, Davide Mei, J. Helen Cross, Renzo Guerrini

Research output: Contribution to journalArticlepeer-review


Purpose: Mutations of the α1 subunit sodium channel gene (SCN1A) cause severe myoclonic epilepsy of infancy (SMEI). Mutations of SCN1A have been found in 40 to 100% of SMEI patients and are de novo in the majority of individuals. Methods: We studied two sisters with SMEI and their father with febrile seizures. Results: SCN1A screening revealed a splice-site mutation in both sisters. The mutation was inherited from their father in whom, however, a mosaicism was found, with 37% of ectodermal derivative cells carrying the mutation. Conclusions: In this family, a SCN1A mosaic mutation correlated with the milder phenotype, whereas the full heterozygous mutation caused SMEI. The possibility of mosaic mutations must, therefore, also be taken into account for genetic counseling and determining the recurrence risk in patients with SMEI.

Original languageEnglish
Pages (from-to)1737-1740
Number of pages4
Issue number10
Publication statusPublished - Oct 2006


  • Generalized epilepsy with febrile seizures plus
  • Mosaic mutation
  • SCN1A gene
  • Severe myoclonic epilepsy of infancy

ASJC Scopus subject areas

  • Clinical Neurology
  • Neuroscience(all)


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