Alzheimer's Disease Risk Allele Frequencies Differ Based on Ethnicity in HABLE Cohort

Purpose: Alzheimer's Disease (AD) or other related dementias remain a significant burden on our aging population. Here we evaluate the top 10 AD risk alleles previously reported by Kunkle et al. (2018) in Mexican Americans and non-Hispanic whites enrolled in the Healthy Aging Brain in Latino Elders Study (HABLE) cohort to see if allele frequencies vary based on ethnicity. Methods: DNA was extracted from buffy coat samples (n = 1635) on the Hamilton robotic system with the Mag-Bind Blood & Tissue DNA HDQ 96 Kit. Genotyping was performed per manufacturer's protocol using the Illumina Infinium Global Screening Array (GSA) and analyzed with Genome Studio 2.0. Samples with call rates less than 98% were repeated or excluded. Allele and genotype frequencies were calculated using standard statistics by compiling the top ten AD risk alleles from Kunkle et al. (2018) and measuring their frequencies in the HABLE cohort. Results: Our data suggest varying degrees of allele and genotype frequencies among the top 10 risk conferring SNPs between Mexican Americans and Non-Hispanic Whites. In particular, we show some instances (BIN1, PTK2B) where the heterozygotes are in higher frequency than homozygotes. 8 of our evaluated SNPs show a difference greater than 5% between the two ethnicities. Conclusion: It may be beneficial to further study the top AD risk alleles among different ethnicities to determine if there are variable frequencies in those populations. We plan to expand and continue this work in other ethnicities and further elaborate on these differences to promote ethnicity targeted diagnostics and help reduce health disparities in medicine and science.