Sex-specific genetic drivers of memory, executive functioning and language in older adults

We previously published a sex-specific genetic analysis of memory performance, a strong endophenotype of Alzheimer's disease (AD), whereby we identified numerous sex-specific genetic loci, candidate genes, and biological pathways associated with late-life memory performance. Here, we expand on this work by conducting a sex-specific, cross-ancestral genetic analysis of three cognitive domains related to cognitive change in AD: memory, executive functioning, and language. This analysis was comprised of 10 aging and AD cohorts, including 33,918 older adults with a mean age of 73 years old, 57% females and 59% cognitively unimpaired. First, we evaluated SNP-based heritability across all three cognitive domains, both with baseline performance and longitudinal cognitive decline, and determined that the heritability across all measures was comparable across sexes. Next, we conducted cross-ancestry, genome-wide meta-analyses across the 10 cohorts, identifying three novel genome-wide significant loci relating to cognition in a sex-specific manner. First, we identified a locus (rs13387871), associated with female-specific language decline, and functional annotation suggested VRK2 as a candidate gene of interest; VRK2 is a published candidate gene for multiple neuropsychiatric traits, especially those involving language ability. Then we identified two sex-specific loci among individuals with cognitive impairment. The first locus was associated with male-specific memory decline (rs12501200), and functional annotation suggested DCHS2 as a gene of interest; notably DCHS2 is a published candidate gene for AD age-at-onset and tau pathology burden. Finally, among cognitively impaired individuals, we identified a sex-interaction with baseline executive functioning (rs1380012), and functional annotation suggested AGA as a candidate gene of interest. We additionally identified numerous biological pathways associated with sex-specific AD-related cognitive performance, including regulation of meiosis, fatty acid synthesis, and chromatin silencing. Our comprehensive genetic analysis of memory, executive functioning, and language performance highlighted genetic loci, genes, and biological pathways that relate to sex-specific cognitive change in both preclinical and clinical AD.