Over the last few years, an increasing number of association studies have provided compelling evidence regarding the role of the ADH1C gene in alcohol and drug dependence as well as in alcohol-related liver disease, cirrhosis, and pancreatitis. However, the results have been inconsistent, partially because each study obviously involved a limited number of subjects, and some were underpowered to the extent that there was not enough information to demonstrate a significant association. Second, the findings are complicated by the use of different ethnicities, sampling strategies, or genotyping procedures (e.g., the rates of alcohol abuse and alcohol-related medical diseases differ across various populations). Third, the low prevalence of Val350Val individuals in some Asian populations makes it particularly difficult to determine the effect of homozygous individuals without evaluating large samples.
