Evidence for S284L mutation of the CHRNA4 in a white family with autosomal dominant nocturnal frontal lobe epilepsy

Purpose: To identify mutations of the neuronal nicotinic acetylcholine receptor alpha4 subunit gene (CHRNA4) responsible for autosomal dominant nocturnal frontal lobe epilepsy (ADNFLE) in a group of white patients. Methods: A group of 47 patients from 21 unrelated families with ADNFLE were screened for mutations in CHRNA4. Clinical features and EEG findings in the patients were consistent with those reported in the literature for other affected families. The entire gene was amplified from genomic DNA by polymerase chain reaction (PCR) followed by multitemperature single-strand conformation polymorphism analysis (MSSCP) and sequencing. Results: A c.851C > T transition in exon 5 of CHRNA4 was identified in three affected individuals from two generations of the same family, but not in the remaining patients or in 100 healthy volunteers. This mutation caused an S284L substitution in the transmembrane domain M2 segment of the alpha4 subunit of the neuronal nicotinic acetylcholine receptor. The same mutation had previously been detected in a single Japanese family with ADNFLE, and in an Australian woman with a sporadic form of NFLE. Conclusions: This is the first report of an occurrence of c.851C > T transition in a white family with ADNFLE.