Investigation of Gene Polymorphisms Leading to Formation of Tau and Beta-amyloid in Alzheimer’s disease

Abstract

Alzheimer’s disease, a chronic neurodegenerative disease, is the most common cause of dementia. Clusterin (CLU) is a protein that is thought to regulate pathways such as apoptosis and the inflammation associated with Alzheimer’s disease. Sortilin-related Receptor 1 (SORL1) proteins bind to amyloid precursor proteins and effectively decrease the amount of toxic Aβ proteins. The Complement receptor 1 (CR1) gene encodes a protein considered to play crucial roles in development and progression of various autoimmune and infectious diseases. The study group consists of 68 patients with Alzheimer's disease and 75 healthy individuals without any neurological disease were included to the control group. CLU and CR1 genotypes were determined with PCR-RFLP while SORL1 genotypes were determined using capillary sequencing. SPSS 17 program was used for statistical analyses and p<0.05 was considered as statistically significant. The allelic association test showed that allelic distributions of rs202081077 on the Clusterin gene, rs641120 on SORL1 gene and rs202213311 on CR1 gene were significantly different in Alzheimer’s patients. Clusterin (rs202081077) TT genotype and T allele frequency (p=0.044856, p=0.003871); SORL1 (rs641120) TT genotype and T allele frequency (p=0.000001, p=0.00000); CR1 (rs202213311) GG genotype and G allele frequency were higher in the Alzheimer group than in the control group (p˂0.05). These polymorphisms may be effective in Alzheimer's disease.

Keywords: Alzheimer’s disease, polymorphism, SORL1, CLU, CR1