Familial occurrence of febrile seizures and epilepsy in severe myoclonic epilepsy of infancy (SMEI) patients with SCN1A mutations

Maria Margherita Mancardi, Pasquale Striano, Elena Gennaro, Francesca Madia, Roberta Paravidino, Sara Scapolan, Bernardo Dalla Bernardina, Enrico Bertini, Amedeo Bianchi, Giuseppe Capovilla, Francesca Darra, Maurizio Elia, Elena Freri, Giuseppe Gobbi, Tiziana Granata, Renzo Guerrini, Chiara Pantaleoni, Antonia Parmeggiani, Antonino Romeo, Margherita SantucciMarilena Vecchi, Pierangelo Veggiotti, Federico Vigevano, Angela Pistorio, Roberto Gaggero, Federico Zara

Research output: Contribution to journalArticle

Abstract

Purpose: The role of the familial background in severe myoclonic epilepsy of infancy (SMEI) has been traditionally emphasized in literature, with 25-70% of the patients having a family history of febrile seizures (FS) or epilepsy. We explored the genetic background of SMEI patients carrying SCN1A mutations to further shed light on the genetics of this disorder. Methods: We analyzed the occurrence of FS and epilepsy among first- and second-degree relatives (N = 867) of 74 SMEI probands with SCN1A mutations (70 de novo, four inherited) and compared data with age-matched and ethnically matched control families. Familial clustering and syndromic concordance within the affected relatives in both groups were investigated. Results: The frequency of FS or epilepsy in relatives of SMEI patients did not significantly differ from that in controls (FS: 13 of 867 vs. 12 of 674, p = 0.66; epilepsy: 15 of 867 vs. six of 674, p = 0.16). Different forms of epilepsy were identified in both relatives of SMEI probands and controls. Twenty-eight relatives with FS and epilepsy were distributed in 20 (27%) of 74 SMEI families; among the controls, 18 affected relatives were clustered in 13 (18.5%) of 70 families. No pedigree showed several affected members, including the four with inherited mutations. Conclusions: A substantial epileptic family background is not present in our SMEI patients with SCN1A mutations. These data do not confirm previous observations and would not support polygenic inheritance in SMEI. The investigation of the family background in additional series of SMEI patients will further shed light on the genetics of this syndrome.

Original languageEnglish
Pages (from-to)1629-1635
Number of pages7
JournalEpilepsia
Volume47
Issue number10
DOIs
Publication statusPublished - Oct 2006

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Keywords

  • Genetics
  • Severe myoclonic epilepsy of infancy
  • Voltage-gated sodium channel α subunit type A

ASJC Scopus subject areas

  • Clinical Neurology
  • Neuroscience(all)

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