A novel mutation of the nicotinic acetylcholine receptor gene CHRNA4 in a Chinese patient with non-familial nocturnal frontal lobe epilepsy.

So far, only two mutations in the CHRNA4 gene (in three studies) and one mutation in the CHRNB2 gene had been identified in the patients with sporadic nocturnal frontal lobe epilepsy (NFLE). The absence of mutations in the candidate genes in the majority of sporadic NFLE patients suggest that they are rare loci for the disease, but the necessity of performing genetic testing for sporadic cases should not be neglected. We designed mutation screening of exon 5 of CHRNA4, exon 5 of CHRNB2, and exon 6 of CHRNA2 in a group of 56 Chinese sporadic NFLE cases. A de novo missense mutation in the transmembrane domain M2 segment of the α4 subunit of the neuronal nicotinic acetylcholine receptor, c.823A>T, was found in a 15 year-old right-handed male, but was not observed in his parents and 400 control chromosomes. The mutation decreased the surrounding hydrophobicity and slightly altered secondary structure of the protein. No mutations were found in CHRNB2 and CHRNA2.