In an attempt to identify novel genetic variants associated with sporadic Alzheimer's disease (AD), a genome-wide association study was performed on a population isolate from Eastern Canada, referred to as the Québec Founder Population (QFP). In the QFP cohort, the rs10406151 C variant on chromosome 19 is associated with higher AD risk and younger age at AD onset in APOE4- individuals. After surveying the region surrounding this intergenic polymorphism for brain cis-eQTL associations in BRAINEAC, we identified PPP2R1A as the most likely target gene modulated by the rs10406151 C variant. PPP2R1A mRNA and protein levels are elevated in multiple regions from QFP autopsy-confirmed AD brains when compared with age-matched controls. Using an independent cohort of cognitively normal individuals with a parental history of AD, we found that the rs10406151 C variant is significantly associated with lower visuospatial and constructional performances. The association of the rs10406151 C variant with AD risk appears to involve brain PPP2R1A gene expression alterations. However, the exact pathological pathway by which this variant modulates AD remains elusive.
Keywords: APOE4; Alzheimer's disease; Genome-wide association study; PPP2R1A; Quebec Founder Population; Visuospatial performance.
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