Although single nucleotide polymorphisms rs429358 and rs7412 in the apolipoprotein E gene (APOE) are widely investigated to analyze APOE alleles, there are no data on their association with Alzheimer's disease (AD) dementia in a Serbian population. This study aimed to investigate the distribution of APOE e2/e3/e4 alleles in patients with dementia due to AD and cognitively unimpaired subjects and to assess the association of the APOE e4 allele with disease risk in the Serbian population. A case-control study included patients with dementia due to AD and cognitively unimpaired individuals. APOE rs429358 and rs7412 were analyzed using the Real-Time PCR method with allele-specific TaqMan assays, followed by APOE e2/e3/e4 allele carrier status analysis. Patients had a significantly higher frequency of the APOE e4 allele than the control group (P<0.001). The APOE e4 allele was found to be associated with a 3-fold higher risk of AD dementia compared to the reference e3 allele (P<0.001). In conclusion, this is the first study to suggest that carriers of the APOE e4 allele have a higher risk of developing dementia due to AD than those who carry the APOE e3 allele in the Serbian population. [ABSTRACT FROM AUTHOR]