This work is an extension of that by Rana et al. (2009) and Haller et al. (2012) who re-sequenced CHRNA5 (and other) genes in African-Americans. Similar to their results, we find few novel variants in CHRNA5, and those that we did find are mostly rare in the African-American population (Table 1). Nonetheless, we describe a novel frame-shift mutation that likely results in nonsense-mediated decay of the transcript from the aberrant allele (Figure 1). Several limitations of our study should be acknowledged: We re-sequenced mainly the coding (exonic) portions of the CHRNA5 gene, which, although some intronic variants were found, excluded large portions of CHRNA5 that might have functional relevance to CHRNA5 expression levels. The boundaries of the region associated with nicotine dependence stretches both upstream and downstream of CHRNA5 (Saccone et al, 2010), incorporating other genes (i.e. CHRNA3/B4) that we have not re-sequenced in this study, but that others reported to contain variants that are protective for nicotine dependence (Haller et al, 2012). Finally, we conclude that, in African-Americans, variants (common or rare) in genes other than CHRNA5 most likely
