Thus, the presence of the ADH1C*2 allele would be associated with a slightly reduced oxidizing capacity, whereas the presence of ADH1B*2 and ADH1B*3 alleles would be associated with a substantially higher oxidative capacity (i.e., more rapid ethanol oxidation to acetaldehyde). These calculations are rough approximations, however, because they assume that the different alleles are expressed at equal levels. In reality, other factors, including liver size and differences in gene expression, can lead to differences even between individuals carrying the same alleles (i.e., with the same genotype). For example, among healthy young European Americans, almost all of whom are homozygous for ADH1B*1, actual ethanol elimination rates have been shown to differ about four-fold (O’Connor et al. 1998).
