G allele is less common in European ancestry (0.17) and virtually absent in individuals of African ancestry (0.01). There are no AI/AN genotypes available in HapMap or the 1000 Genomes databases. Unpublished data from our laboratory shows that the G allele is common in the Southeastern American Indian (0.31) and Plains American Indian (0.25) samples whereas the frequency in the Southwestern American Indian sample (0.18) is the same as in Europeans. Therefore, about half of Southeastern American Indians, one third of Southwestern American Indians and three quarters of Japanese are likely to respond well to naltrexone if this medication is administered along with psychosocial treatments.
