Overall, there is evidence that ADH1C*1 is protective against alcohol dependence, but the LD in the region, particularly across ADH1B and ADH1C, makes interpretation of many of the studies difficult. In particular, the high LD with ADH1B*2 (D’ = 0.91 in Europeans, although r2 is low) is generally not acknowledged. Given the strong effect of ADH1B*2 on these phenotypes conditional analyses are important. Another way to disambiguate the situation would be to separately analyze the data in the large group without any ADH1B*2 alleles, as was done in the Danish study (Tolstrup et al., 2008).
