African Americans have about double the risk of dementia as their non-Hispanic white peers. How much of this is genetics, how much is environment? With the biggest genome-wide association study on African Americans to date, researchers led by Brian Kunkle at the University of Miami in Florida and Christiane Reitz at Columbia University in New York inched closer to answering this question. At just more than 8,000 participants, the study was still small by GWAS standards. It identified 11 novel AD risk loci, including four common variants and seven rare ones. Many of the exact genes differed from those identified in larger studies done on predominantly white participants, but their functions—in immunity, intracellular trafficking, and lipid processing—mostly overlapped. One exception was kidney development, which newly emerged in this study of black Americans.
- AD GWAS in African Americans included 8,000 participants.
- Of 11 novel risk loci identified, four were common, seven rare.
- Immunity, trafficking, lipid processing, and kidney development implicated in disease risk.
Myriad factors likely contribute to higher dementia rates among black Americans (Tang et al., 2001). In addition to having a higher incidence of comorbidities such as hypertension and diabetes, this population is also disadvantaged in access to quality healthcare, education, and in socioeconomic status. Genetics might also play a role; alas, unearthing disease-associated variants requires massive numbers of samples, and the largest GWAS so far have included mostly non-Hispanic white populations (Oct 2018 conference news).