RESUMO
The association between ApoE E4 and dementia is reported in Alzheimer's disease and other dementia such as in multi-infarct dementia. OBJECTIVES: To examine the association between apolipoprotein E genotype (ApoE) and dementia in Thai elderly and patients to examine the alleles frequencies of ApoE in a Thai population. MATERIAL AND METHOD: Seventy-eight cases and ninety-four controls from a community based population were recruited. Their ages were all over 50 years. Dementia was diagnosed by DSM IV criteria. Blood was taken and stored for DNA extraction and for restriction enzyme analysis of ApoE genotype. Descriptive analysis and odds ratios from SPSS 9.0 program were used in this study. RESULTS: Alleles frequencies of ApoE E2, E, E4 in normal controls were 0.03, 0.80, 0.17 and alleles frequencies of ApoE E3, E4 in dementia subjects were 0.71 and 0.29, respectively. Odds ratios for dementia risk of apolipoprotein genes were as follows: 0.62 for ApoE E3 and 1.98 for ApoE E4. In this study, forty-two dementia subjects had Alzheimer's disease. Fifty nine point five per cent of Alzheimer's disease subjects carried ApoE E4 (positive predictive value is 0.60). CONCLUSION: Thai elderly carry ApoE genotype distribution similar to that reported in other ethnic groups. Bearing ApoE E4 gene increases the risk of developing dementia. The use of ApoE genotyping can only be a diagnostic adjunct for Alzheimer's disease.