How understudied populations have contributed to our understanding of Alzheimer's disease genetics

The majority of genome-wide association studies have been conducted using samples with a European genetic background. As a field, we acknowledge this limitation and the need to increase the diversity of populations studied. A major challenge when designing and conducting such studies is to assimilate large samples sizes so that we attain enough statistical power to detect variants associated with disease, particularly when trying to identify variants with low and rare minor allele frequencies. In this study, we aimed to illustrate the benefits, to genetic characterization of Alzheimers disease (AD), in researching currently understudied populations. This is important for both fair representation of world populations and the translatability of findings. To that end, we have conducted a literature search to understand the contributions of studies, on different populations, to AD genetics. We systematically quantified the number of studies identifying mutations in known disease-causing genes, in a world-wide manner, and discussed the contributions of research in understudied populations to the identification of novel genetic factors in this disease. Additionally, we compared the effects of genome-wide significant SNPs across populations by focusing on loci that show different association profiles between populations (a key example being APOE). This work functions to both highlight how understudied populations have furthered our understanding of AD genetics, and to help us gage our progress in understanding the genetic architecture of this disease in all populations.