Potential genetic biomarkers in the early diagnosisof Alzheimer disease: APOE and BIN1

Authors: GÜLHAN KAYA, ESRA GÜNDÜZ, MURADİYE ACAR, ÖMER FARUK HATİPOĞLU, BURCU ACAR, ATİLLA İLHAN, MEHMET GÜNDÜZ

Abstract: Background/aim: Alzheimer disease (AD) is triggered by interactions of multiple genetic and environmental factors. The APOE gene E4 allele is the best-known risk factor for AD, yet it represents a small ratio of genetic factors. According to genome-wide association studies, the BIN1 gene is the second important risk factor for AD, following the APOE gene. We aimed to identify a novel biomarker indicating susceptibility to AD by investigating APOE alleles and BIN1 gene polymorphisms in a Turkish population. Materials and methods: Fifty-three AD patients and 56 controls were included to examine polymorphism and allele frequency of the APOE and BIN1 genes. Genomic DNAs were isolated from whole blood by SDS/proteinase K treatment, phenol-chloroform extraction, and ethanol precipitation. RFLP was done for identification of polymorphisms in the APOE gene and allele-specific PCR was used for the BIN1 gene. Results: Frequency of the APOE E4 allele was higher in the AD patient group, while the frequency of the E2 allele was higher in controls. The E4/E4 genotype was detected in the AD patient group, while this genotype was not observed in the controls. The frequencies of BIN1 alleles were similar in both groups. Conclusion: There was a strong association between AD and the APOE E4 allele, while no such relation was observed with BIN1 gene polymorphism.

Keywords: Alzheimer disease, APOE, BIN1, polymorphism, biomarker, RFLP

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