breath ethanol levels among 412 Australian twins (27), and similarly a larger and more recent study of ADH variation and alcohol metabolism among 812 Australian twins and relatives (MAF = 3.5%) could not find sufficient evidence for an effect of rs1229984 on blood or breath ethanol concentrations (22). One study from Japan, where the A allele is extremely prevalent (MAF = 53%), failed to detect an effect on blood levels of acetaldehyde following light drinking (N = 68) (49), but another reported that extreme levels of drinking in alcoholics (N = 80) gave rise to higher blood ethanol and to a lesser extent blood acetaldehyde levels the morning after heavy drinking for carriers of the ancestral G allele (slower metabolizers) (29).
