The genes involved in alcohol metabolism represent obvious candidate genes for alcohol misuse disorders, and thus, have been the focus of much research in a number of different ethnic populations. The seven alcohol dehydrogenase (ADH) genes, ADH7, ADH1C, ADH1B, ADH1A, ADH6, ADH4, and ADH5, are located in a single cluster on chromosome 4q21–24 with each gene coding for a unique isozyme. The relation between this chromosomal region and alcohol dependence has been reported in a number of linkage studies of diverse ethnic groups including Native Americans [20], and association studies have now produced replicable evidence of association between polymorphisms in these genes and alcohol-related phenotypes in Native Americans. For example, two functional polymorphisms were identified in the ADH1B gene that have been used to describe the presence of three alleles, ADH1B*1, ADH1B*2 (identified by rs1229984), and ADH1B*3 (identified by rs2066702). The ADH1B*2 and ADH1B*3 alleles have demonstrated a protective relation with alcohol dependence and related phenotypes in Asian and Caucasian samples and African-American samples respectively, and both alleles have been observed in the studied Native American populations. The ADH1B*2 allele
