As the 118A>G SNP changes an amino acid, it has been generally assumed that it is the causative variant for the phenotypes associated with it. There is a possibility that other variants, which are in LD with 118A>G, contribute to these phenotypes. The mixed results for 118A>G may be explained in part by different and/or population-specific haplotype patterns. The 118G allele was shown to be represented by a specific haplotype that includes several SNPs from the 5′ flanking region of the gene in EA subjects, but appears in two haplotypes in the Asian HapMap population. The major haplotype is similar to the one found in EA subjects and the second one includes other SNP combinations (Levran et al. 2011).
