In the Asian populations, the ALDH2 gene was located within a large region spanning 13 haplotype blocks with strong LD, and more than ten genes were found within this LD structure (Figure 5). Compared with the Asian populations, the European-ancestry populations showed stronger LD in this large structure, which was composed of three big haplotype blocks (supplementary Figure 3). Two other genes (BRAP and ACAD10) share the same haplotype block with ALDH2. Although it is unlikely that the association of this SNP was due to linkage disequilibrium with a different closely-mapped polymorphism at ALDH2 or another gene considering both the strength of the association and the compelling biological rationale, it is still desirable to investigate other variants within the large structure in subsequent studies. For example, one SNP rs4646776 was in strong LD with rs671 based on the 1000 Genomes Project (11,747 base pair; r2 = 0.81; and recombination rate = 0.99) (supplementary Figure 4).
