A major role of the nicotinic acetylcholine receptor gene CHRNA2 in autosomal dominant nocturnal frontal lobe epilepsy (ADNFLE) is unlikely

Abstract

Autosomal dominant nocturnal frontal lobe epilepsy (ADNFLE) is known to be caused by mutations in the transmembrane regions of the neuronal nicotinic acetylcholine receptor (nAChR) genes CHRNA4 and CHRNB2. A third nAChR gene, CHRNA2, has been recently reported as mutated in an Italian family with nocturnal frontal lobe epilepsy, nocturnal wandering and ictal fear. We have now evaluated the role of CHRNA2 in families with "classical" ADNFLE. Mutation screening was performed in 47 families by amplification and subsequent sequencing of part of CHRNA2 exon 6 containing transmembrane regions 1-3. Detected variants were tested in a case-control association study. No mutations were identified in the parts of CHRNA2 that contribute to the ion pore. Sequencing identified a novel synonymous nucleotide exchange (c.771C/T) that was also present in two of 78 controls and is therefore likely to be non-pathogenic. The absence of mutations in our sample of 47 families renders a major role of CHRNA2 in ADNFLE unlikely.