A Validation Study of Vascular Cognitive Impairment Genetics Meta-Analysis Findings in an Independent Collaborative Cohort

Vascular cognitive impairment (VCI), including its severe form, vascular dementia (VaD), is the second most common form of dementia. The genetic etiology of sporadic VCI remains largely unknown. We previously conducted a systematic review and meta-analysis of all published genetic association studies of sporadic VCI prior to 6 July 2012, which demonstrated that APOE (ϵ4, ϵ2) and MTHFR (rs1801133) variants were associated with susceptibility for VCI. De novo genotyping was conducted in a new independent relatively large collaborative European cohort of VaD (n_max=549) and elderly non-demented samples (n_max=552). Where available, genotype data derived from Illumina's 610-quad array for 1210 GERAD1 control samples were also included in analyses of genes examined. Associations were tested using the Cochran-Armitage trend test: MTHFR rs1801133 (OR=1.36, 95 CI 1.16-1.58, p=<0.0001), APOE rs7412 (OR=0.62, 95 CI 0.42-0.90, p=0.01), and APOE rs429358 (OR=1.59, 95 CI 1.17-2.16, p=0.003). Association was also observed with APOE epsilon alleles; ϵ4 (OR=1.85, 95 CI 1.35-2.52, p=<0.0001) and ϵ2 (OR=0.67, 95 CI 0.46-0.98, p=0.03). Logistic regression and Bonferroni correction in a subgroup of the cohort adjusted for gender, age, and population maintained the association of APOE rs429358 and ϵ4 allele.