An overview of the genetic susceptibility to alcoholism.

AIMS: Alcoholism is a multifactorial, genetically influenced disorder. It is a major health and social issue, a highly frequent disease and a cause of premature death. It is also the most expensive addictive disorder due to morbidity, mortality, societal and legal problems. Besides their involvement in alcohol-related fatalities, forensic scientists are also required to assess driving and working ability as well as permanent invalidity due to alcohol-related conditions. Greater knowledge of the genetic basis of alcoholism could improve prevention by identifying specific risk factors and mechanisms, leading to effective therapeutic strategies and eventually to personalized treatments.

METHODS: This overview of the recent scientific literature on the genetic basis of alcoholism summarizes the analytical strategies currently applied to the identification of candidate genes involved in alcohol-use disorders (AUDs) and discusses some genes and related phenotypes that have been shown to influence the risk of alcoholism.

RESULTS: Alcoholism is a complex heterogeneous genetic disease. It is a quantitative disorder, in which the combined incidence of multiple genetic factors and environmental factors varies from one subject to another. Family, twin and adoption studies indicate that 50-60% of the risk of alcoholism is due to genetic factors. Risk loci for AUDs include both genes involved in alcohol pharmacokinetics and pharmacodynamics as well as genes moderating neurophysiological responses such as impulsivity, disinhibition, sensation-seeking and externalizing behaviours. Alcoholism also co-exists with other addictions and psychiatric disorders. Such co-morbidity suggests the existence of shared aetiological factors.

CONCLUSIONS: Despite several genes that influence the risk for AUDs having been identified, the genetic bases of alcoholism remain largely unknown. Particularly the mechanism of action or the understanding of the physiology of some genes, as well as the gene-environment interactions, is still unknown. Technological progress and advances in transcriptomics, epigenomics and proteomics are expected to enhance our knowledge of the genetic susceptibility to alcoholism.