Genetic Association between Presenilin 2 Polymorphisms and Alzheimer's Disease and Dementia of Lewy Body Type in a Japanese Population

BACKGROUND/AIMS: Mutations in the presenilin 2 (PSEN2) gene cause familial Alzheimer's disease (AD). Common polymorphisms affect gene activity and increase the risk of AD. Nonsynonymous polymorphisms in the PSEN2 gene showed Lewy body dementia (LBD) phenotypes clinically. Therefore, we aimed to investigate whether PSEN2 gene polymorphisms were associated with AD or LBD. METHODS: Seven single nucleotide polymorphisms (SNPs) of the gene were analyzed using a case-control study design comprising 288 AD patients, 76 LBD patients, and 105 age-matched controls. RESULTS: Linkage disequilibrium (LD) examination showed strong LD from rs1295645 to rs8383 on the gene in our cases from Japan. There were no associations between the SNPs studied here and AD onset, and haplotypic analyses did not detect genetic associations between AD and the PSEN2 gene. Although the number of the cases was small, the SNPs studied did not modify the risk of developing LBD in a Japanese population. CONCLUSION: The common SNPs of the PSEN2 gene did not affect the risk of AD or LBD in a Japanese population. Because genetic variability of the PSEN2 gene is associated with behavioral and psychological symptoms of dementia (BPSD) in AD and LBD, further detailed analyses considering BPSD of both diseases would be required.