As noted, ALDH1A1 polymorphisms are also found to occur at low frequencies in African Americans. The association of ALDH1A1 variants with risk for alcohol dependence is unclear (Ehlers et al., 2004; Moore et al., 2007; Spence et al., 2003). Although ALDH1A1 is associated with alcohol metabolism, it is also unclear whether variations in the ALDH1A1 promoter region contribute to differences in alcohol metabolism or alcohol response. In the present study, the frequencies of ALDH1A1 variants (ALDH1A1*2 and ALDH1A1*3) were too low to allow for separate analysis, so participants with these variants were excluded from the analyses, so as not to confound their possible effects on alcohol metabolism with the effects of the tested alleles for ADH1B and ADH1C.
