High levels of alcohol intake are associated with impairment of multiple organs, including brain, liver, pancreas and the immune system. The first stage of liver damage following chronic alcohol consumption is the development of fatty liver, which may be followed by inflammation, apoptosis, fibrosis and cirrhosis. Alcohol and its metabolite acetaldehyde are carcinogens, and excessive alcohol consumption is associated with increased risk for mouth and oropharyngeal cancer, breast cancer and liver cancer. The risk of upper gastrointestinal cancer is increased by a missense variant in the gene encoding aldehyde dehydrogenase (ALDH), which is found in some 500 million East Asians [2]. Depression, epilepsy, hypertension and hemorrhagic stroke occur secondary to alcohol consumption [3]. Finally, alcohol consumption during pregnancy can result in birth defects that comprise fetal alcohol syndrome [4]. The diversity of pathologic effects of alcohol indicates that this drug exerts toxicity through multiple mechanisms, each of which can be modulated by different genetic variants.
