As challenging as it will be to identify genes involved in alcohol dependence, decisions regarding the use and application of that knowledge will perhaps be even more challenging. How the information regarding genetic susceptibility to alcoholism (and other disorders) will be conveyed to and used by the public is still undetermined. These issues are especially complex because any genes found to be involved in alcoholism are not likely to cause the disease directly but only increase or decrease alcoholism susceptibility. Some of the issues that are likely to face alcohol researchers once they identify susceptibility genes can be illustrated using the example of Alzheimer’s disease (AD) and the apolipoprotein E (ApoE) gene. Several alleles of this gene exist, one of which—the E4 allele—is associated with an increased risk for AD. People carrying at least one E4 allele have an estimated lifetime risk of AD of approximately 30 percent, whereas the risk of AD is only 9 percent in people who carry no E4 allele (Post et al. 1997). However, most people who carry an E4 allele will never manifest the
