The Study of Synergy between the BchE-k Variant and the ApoE Gene in the Alzheimer Dementia of the Korean Population

The Apolipoprotein E type 4 allele (ApoE ${\varepsilon}4$) is genetically associated with the common late onset familial and sporadic forms of Alzheimer's disease. The BchE-k variant, which is the common variant of the BchE gene, has been reported to show allelic association with AD in subjects who are also carriers of the ${\varepsilon}4$ allele of the ApoE, especially in subjects over the age of 75. This study was performed to evaluate the distribution of the ApoE and the BchE genotypes in the healthy and AD groups and to evaluate the synergy between the BchE-k variant and the ApoE ${\varepsilon}4$ in AD. The ApoE and the BchE genotypes were determined in DNA samples from 610 healthy people and 60 LOAD patients by using ARMS by standard agarose gel electrophoresis. The effect of the ApoE ${\varepsilon}4$ was closely related to AD(p<0.05). A comparison between the AD patients and the healthy individuals, both with the ${\varepsilon}4$ allele, indicated an interaction between the BchE-k and the ApoE ${\varepsilon}4$(p<0.05). The association of the BchE-k with AD was limited to carriers of the ApoE ${\varepsilon}4$ allele, among whom the presence of the BchE-k gave an odds ratio of AD 3.48 (95% C.I. 1.3-9.2). Therefore, these results suggested that further evidence of an association between the ApoE ${\varepsilon}4$ and LOAD, and the BchE-k acts in synergy with the ApoE ${\varepsilon}4$ as a susceptibility gene for AD.