[Genes polymorphism of BIN1 and ApoE in patients with amnestic mild cognitive impairment from Enshi Tujia area]

Association Analysis of Polymorphisms in BIN1, MC1R, STARD6 and PVRL2 with Mild Cognitive Impairment in Elderly Carrying APOE ε4 Allele

BACKGROUND

Apolipoprotein (APOE) ε4 is recognized as an independent risk factor for mild cognitive impairment (MCI). However, not everyone with the ε4 allele develops MCI, suggesting that other susceptibility genes exist. This study aimed to identify MCI susceptibility genes, including BIN1, MC1R, STARD6, and PVRL2, in elderly Han Chinese and to verify their association with APOE ε4 allele in MCI onset.

METHODS

To determine whether polymorphisms in BIN1 (rs6733839, rs7561528), MC1R (rs2228479), STARD6 (rs10164112), and PVRL2 (rs6859) occurred in elderly MCI patients carrying APOE ε4 allele, we carried out a case-control study including 285 MCI patients and 326 healthy controls.

RESULTS

Statistically significant differences in the proportion of APOE ε4 carriers, and BESCI, ADAS-cog, and CNT scores existed between the NC and MCI groups (all P < 0.01). Frequencies of the rs10164112 T and rs6859 A alleles were significantly higher in the latter than in the former (P = 0.01; 0.029). However, no significant differences in allele and genotype distribution of BIN1 (rs6733839, rs7561528) and MC1R (rs2228479) existed between samples in our two groups (all P > 0.05). When stratified by APOE ε4 status (carriers/non-carriers), genotype frequencies of BIN1 rs7561528, STARD6 rs10164112, and PVRL2 rs6859 among the four groups (NCε4+, NCε4-, MCIε4+, MCIε4-) were significantly different. Additionally, our results suggest a significant association between MCI and BIN1 rs7561528, STARD6 rs10164112, and PVRL2 rs6859 (all P<0.05) in elderly carriers.

CONCLUSION

This suggests that among the Han Chinese, MCI in elderly APOE ε4 carriers may be related to the BIN1 (rs7561528), STARD6 (rs10164112) and PVRL2 (rs6859). Genotype AA of rs7561528 and TT of rs10164112 might be protective factors against MCI in elderly APOE ε4 carriers.

Identification of Alzheimer's Disease-Related Genes Based on Data Integration Method

Alzheimer disease (AD) is the fourth major cause of death in the elderly following cancer, heart disease and cerebrovascular disease. Finding candidate causal genes can help in the design of Gene targeted drugs and effectively reduce the risk of the disease. Complex diseases such as AD are usually caused by multiple genes. The Genome-wide association study (GWAS), has identified the potential genetic variants for most diseases. However, because of linkage disequilibrium (LD), it is difficult to identify the causative mutations that directly cause diseases. In this study, we combined expression quantitative trait locus (eQTL) studies with the GWAS, to comprehensively define the genes that cause Alzheimer disease. The method used was the Summary Mendelian randomization (SMR), which is a novel method to integrate summarized data. Two GWAS studies and five eQTL studies were referenced in this paper. We found several candidate SNPs that have a strong relationship with AD. Most of these SNPs overlap in different data sets, providing relatively strong reliability. We also explain the function of the novel AD-related genes we have discovered.