Previous re-sequencing studies have been done to assess the contribution of rare variants in the CHRNA5/A3/B4 gene cluster to the etiologies of various disorders, such as megacystis-microcolon-hypoperistalsis syndrome (MMIHS – A3/B4) (Lev-Lehman et al, 2001), autosomal dominant nocturnal frontal lobe epilepsy (ADNFLE – A5/A3/B4) (Duga et al, 2001) and sporadic amyotrophic lateral sclerosis (SALS – A3/B4) (Sabatelli et al, 2009). Whereas these prior studies were mainly on people of European descent, Rana et al (2009) re-sequenced the CHRNA5/A3/B4 genes in 34 Caucasian-American and 30 African-American individuals seeking to discover natural variation in these genes that might explain heritable autonomic traits. More recent CHRNA5/A3/B4 re-sequencing efforts have studied the relationship between common and rare variants in these genes and their association with the Fagerström Test for Nicotine Dependence (Wessel et al, 2010; Haller et al, 2012). Whereas Wessel et al (2010) re-sequenced European-Americans, re-sequencing by Haller et al (2012) included 400 European-Americans and 352 African-Americans; half of each sequenced population being nicotine dependent cases or smoking controls. Here, we re-sequenced the coding regions of the CHRNA5 gene (GenBank: NM_000745.3) in an
