Genetic studies have identified Alzheimer's disease (AD)-associated SNPs in TOMM40 and PVRL2 genes, but the underlying mechanisms remain unknown. We examined their associations and interactions with AD risk and plasma biomarkers among Chinese older adults. This population-based study included 4876 participants. TOMM40(rs2075650) and PVRL2(rs6859) polymorphisms were detected using multiple-polymerase chain reaction amplification. Plasma Aβ40, Aβ42, and t-tau concentrations were measured using SIMOA in a subsample (n = 1257). AD was diagnosed following the international criteria. Data were analyzed using multiple logistic and general linear models. AD was diagnosed in 182 participants. The multiadjusted odds ratio of AD was 6.24 (95% CI 1.73-22.48) for TOMM40GG, 1.47 (0.89-2.42) for PVRL2AA, and 12.87 (3.97-41.73) for having both risk alleles (Pinteraction = 0.0003). Among APOEε3/ε3 carriers, the multiadjusted odds ratio of AD associated with TOMM40AG was 2.90(1.15-7.31). In biomarker subsample, TOMM40GG was significantly associated with lower plasma Aβ42 and the Aβ42-to-Aβ40 ratio (p < 0.05). TOMM40 genotype is differentially associated with AD risk depending on APOE genotype. TOMM40 and PVRL2 genes could interact to substantially increase AD risk, possibly through influencing Aβ metabolism.
Keywords: Alzheimer's disease; Gene-gene interaction; PVRL2; Plasma biomarkers; Population-based study; TOMM40.
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