The allele frequency of CYP2A6*4 in four ethnic groups of China.

The CYP2A6*4 allele, characterized as the whole deletion of this gene, is closely associated with nicotine dependence, cancer susceptibility, and drug responsiveness. The frequency of this molecular variant differs across populations. Although genetic polymorphisms of CYP2A6*4 and its functional results have been reported in Chinese Han population, the allele frequency of CYP2A6*4 was largely unknown in other Chinese ethnic population. In this study, we investigated the allele frequency of CYP2A6*4 in four main ethnic groups of China based on our newly developed quantitative real-time PCR assay. The frequencies of the CYP2A6*4 allele were 7.9%, 15%, 0% and 2% in Han (N=120), Uighur (N=100), Bouyei (N=100) and Tibetan (N=100) (P<0.0001), respectively. This work greatly expanded our understanding of the distribution of CYP2A6*4 in Chinese population and provided more information of different ethnic population's smoking behavior and also in disease susceptibility and drug response.