A plethora of papers on ALDH2 exists in the global literature because of its relevance for public health and human population genetics studies. It may be among the more intensively studied human genes. The large number of publications also provides allele frequency data of ALDH2*504Lys (ALDH2*2 or *487Lys) in many populations, allowing us to determine the detailed geographic distribution of this allele, with the resulting potential to study the demographic histories of populations and the multiple factors affecting the allele frequency. The allele frequency of ALDH2*504Lys ranges from 0 to 40% among the East Asian populations based on the published data, constituting large variation just within East Asia and belying the common impression that the allele is common in all East Asians. We also find that some key areas or ethnic groups in East Asia have not been studied so far for the frequencies of ALDH2 alleles. To assess the detailed distribution of ALDH2*504Lys, we collected relevant data from the literature, and filled many blanks on the global map by typing relevant new population samples.
