CHRNB2 encodes one of several beta subunits. Mutations in this gene are associated with autosomal dominant nocturnal frontal lobe epilepsy.the CHRNB2 gene comprises 6 exons and spans approximately 9 kb of genomic DNA from the ATG start codon to the TGA stop codon. Exon 1 contains the 5-prime untranslated region, the ATG start codon, and parts of the sequence coding for the putative signal peptide. The hydrophobic transmembrane domains I through III are located in the large exon 5. Exon 6 contains the transmembrane domain IV as well as the translation stop codon and the 3-prime untranslated region. The CHRNB2 introns vary in size from 150 bp (intron 2) to 4.5 kb (intron 5). The splicing at the junctions of CHRNB2 introns 2, 3, and 5 occurred between codons (splicing type 0).