Increased sensitivity of the neuronal nicotinic receptor α2 subunit causes familial epilepsy with nocturnal wandering and ictal fear

Paolo Aridon, Carla Marini, Chiara Di Resta, Elisa Brilli, Maurizio De Fusco, Fausta Politi, Elena Parrini, Irene Manfredi, Tiziana Pisano, Dario Pruna, Giulia Curia, Carlo Cianchetti, Massimo Pasqualetti, Andrea Becchetti, Renzo Guerrini, Giorgio Casari

Research output: Contribution to journalArticlepeer-review

Abstract

Sleep has traditionally been recognized as a precipitating factor for some forms of epilepsy, although differential diagnosis between some seizure types and parasomnias may be difficult. Autosomal dominant frontal lobe epilepsy is characterized by nocturnal seizures with hyperkinetic automatisms and poorly organized stereotyped movements and has been associated with mutations of the α4 and β2 subunits of the neuronal nicotinic acetylcholine receptor. We performed a clinical and molecular genetic study of a large pedigree segregating sleep-related epilepsy in which seizures are associated with fear sensation, tongue movements, and nocturnal wandering, closely resembling nightmares and sleep walking. We identified a new genetic locus for familial sleep-related focal epilepsy on chromosome 8p12.3-8q12.3. By sequencing the positional candidate neuronal cholinergic receptor α2 subunit gene (CHRNA2), we detected a heterozygous missense mutation, I279N, in the first transmembrane domain that is crucial for receptor function. Whole-cell recordings of transiently transfected HEK293 cells expressing either the mutant or the wild-type receptor showed that the new CHRNA2 mutation markedly increases the receptor sensitivity to acetylcholine, therefore indicating that the nicotinic α2 subunit alteration is the underlying cause. CHRNA2 is the third neuronal cholinergic receptor gene to be associated with familial sleep-related epilepsies. Compared with the CHRNA4 and CHRNB2 mutations reported elsewhere, CHRNA2 mutations cause a more complex and finalized ictal behavior.

Original languageEnglish
Pages (from-to)342-350
Number of pages9
JournalAmerican Journal of Human Genetics
Volume79
Issue number2
DOIs
Publication statusPublished - Aug 2006

ASJC Scopus subject areas

  • Genetics

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