Haplotype analysis of single nucleotide polymorphisms in VEGF gene for vascular dementia

A case-control study was performed to identify single nucleotide variants of vascular endothelial growth factor (VEGF) gene associated with vascular dementia. Seven SNPs in promoter, 5'-UTR, 3'-UTR, and introns of VEGF gene were identified in 24 Koreans. Three of them, -1154G/A, -7C/T, and 13553C/T, were selected based on allele frequency and linkage disequilibrium (LD), and genotyped in 207 vascular dementia patients and 207 control subjects. Significant association with vascular dementia was not shown (P > 0.05) in the alleles and genotypes of single locus. Subsequent analysis of composing VEGF risk haplotypes associated with vascular dementia was performed with maximum likelihood estimates of their possible haplotypes employing the expectation-maximization (EM) algorithm. Of three-locus haplotypes, only GTC was significantly associated with vascular dementia, conferring a risk of 1.87 (P < 0.05). Of two-locus haplotypes, the risk was observed with the nested forms of the risk haplotype GTC, that is, GT at the loci -1154G/A and -7C/T and TC at the loci -7C/T and 13553C/T (P < 0.05). Our findings suggested some interaction among -1154G/A, -7C/T, and 13553C/T variants in the determination of risk for vascular dementia.