Apolipoprotein E4 and tau allele frequencies among Choctaw Indians.

Apolipoprotein genotyping and tau haplotyping were carried out on a series of cases with dementia and controls from the Choctaw Nation of Oklahoma. Both the Apolipoprotein E4 allele frequency and the tau H2 haplotype frequency were low in the Choctaw compared with Caucasians and there was the possibility that the association between dementia and the E4 allele was weaker than in Caucasians.