Significant variability in frequencies of ALDH alleles have been observed across ethnic groups. ALDH2*2 alleles have been found at moderate rates (20–50%) in samples of northeast Asian heritage (Goedde et al., 1992), and have been found to be associated with lower risk for the development of alcohol dependence (Luczak et al., 2006). Ethnic differences also have been identified in the frequency of the three variants in the ALDH1A1 promoter region: ALDH1A1*1, ALDH1A1*2, and ALDH1A1*3. ADLH1A1*2 alleles have been found at low frequencies (<4%) in Asian, Jewish, Caucasian, Native American, and African American samples; ADLH1A1*3 alleles have been identified at low frequency (≈3%) in samples of Native American and African ancestry (Ehlers et al., 2004; Moore et al., 2007; Spence et al., 2003). There is some evidence that ALDH1A*3 is associated with alcohol dependence in African Americans (Spence et al, 2003), while the association between ADLH1A1*2 and alcohol dependence is mixed (Ehlers et al., 2004; Moore et al., 2007; Spence et al., 2003). The effect of ALDH1A1 variants on alcohol metabolism and alcohol response is unclear.
