Extended genome‐wide association study employing the African Genome Resources Panel identifies novel susceptibility loci for Alzheimer’s Disease in individuals of African ancestry

Background Although African Americans are twice as likely to develop Alzheimer’s Disease (AD), individuals with African ancestry are under‐represented in genetic research of the disease. In the largest AD genome‐wide association studies to date for African‐Americans (Reitz et al. JAMA 2013; Kunkle at al. JAMA Neurol 2021) we previously identified several novel susceptibility loci in addition to APOE, including ABCA7, API5, RBFOX1, and IGF1R. Method We performed a genome‐wide association meta‐analysis of 2,844 AD cases and 6,251 cognitively healthy controls of African ancestry (AA) assembled across 17 different cohorts. Single‐variant association analysis was conducted adjusting for age, sex, principal components, and subsequently APOE, applying logistic regression for case‐control and general estimating equations for family‐based datasets. Within‐study results were meta‐analyzed using METAL, and followed by gene‐based, pathway, scRNA‐seq, and colocalization analyses. Result Single variant meta‐analysis identified a novel genome‐wide significant AD risk locus in the MPDZ gene on chromosome 9p23 (rs141610415, MAF = .002, P = 3.68×10−9). MPDZ (MUPP1) is a vital component of the NMDAR signaling complex in excitatory synapses of hippocampal neurons critical for learning and memory. Two additional novel common loci and 9 novel rare loci approached genome‐wide significance at P