Apolipoprotein E promoter polymorphisms (−491A/T and −427T/C) and Alzheimer’s disease: no evidence of association in the Irish population

Abstract

Alzheimer's Disease (AD) is a progressive neurodegenerative disorder with as yet poorly understood aetiology. Both environmental and genetic factors have been implicated as predisposing factors. The APOE e4 allele is an established genetic susceptibility factor for AD for several populations including the Irish. Polymorphisms (-491A/T and -427T/C) at the promoter region of the APOE gene are postulated to affect the expression of the gene through differential binding of transcription factors. Two APOE promoter polymorphisms (-491A/T and -427T/C) are examined for possible association with AD. Using a case-control study design, a sample of 112 Irish late onset Alzheimer's (LOAD) patients and 107 ethnically matched controls were investigated for association with the above polymorphisms. No evidence of association between any of the examined markers and AD was observed. Haplotype analysis using markers -491A/T and -427T/C in conjunction with the APOE (Hha I) polymorphism revealed significant associations of three haplotypes with AD. However, this association was mainly due to the highly significant association of the APOE e4 allele with AD and not of the promoter variants.