needed to conclusively test these conclusions. Thus far, the reviewed studies suggest that some Native American tribes appear to lack protective variants in alcohol metabolizing enzyme genes that are seen in East Asian and some African population groups (e.g., ALDH2*2 and ADH1B*3), but they provide little overall support for the theory that Native American groups have an “unusual” metabolism of alcohol. Additional genes that code for neurotransmitter receptors and neuromodulators, including OPRM1, CRN1, COMT, GABRA2, MAOA, and HTR3-B, have shown preliminary evidence for association with substance use phenotypes in some tribal groups (table 2). Nonetheless, these associations have also been reported in other ethnic groups, and also provide little evidence to support a genetic association specific to a Native American tribal group or the Native American population as a whole.
