Association Study of the Cd33 Rs3865444 Polymorphism in Alzheimer'S Disease (Ad) in the Northern Iranian Population

Background and aim: alzheimer’s disease (ad) is a complex genetic disorder characterized by the accumulation of amyloid plaques and neurofibrillary tangles (nfts). recent genome-wide association studies have identified single nucleotide polymorphism rs3865444 in the cd33 gene associated with late-onset ad (load) susceptibility. cd33, also known as siglec-3, is a member of sialic acid-binding immunoglobulin-like lectins (siglecs) family expressed on the surface of myeloid progenitor cells, mature monocytes and macrophages. considering that conflicting results have been reported on the role of cd33 rs3865444 polymorphism in load in different populations, our aim in this study was to investigate the relationship between rs3865444 (c) polymorphism and load patients in the north iranian population.methods: we carried out a case-control association study to test for a relationship between the rs3865444 (c) polymorphism and alzheimer’s disease in 104 patients with load and 104 control subjects. the genomic dna and total rna were extracted from peripheral blood white cells using the triton x-100 method and trizol reagent (invitrogen, usa), respectively. genotypes and allele frequencies were determined in two group using multiplex arms-pcr. real-time quantitative pcr (rt- qpcr) was used to investigate the expression of the cd33 gene at transcription levels.results: the distribution of genotype and allele frequencies of rs3865444 polymorphism was no statistically different between load patients and control group (p=0.27 and p=0.08, respectively) while the expression levels of cd33 in peripheral white blood cell were increased in load patients compared to that of control group (p< 0.05).conclusion: results from the case-control study revealed no significant difference between rs3865444polymorphism of the cd33 gene and patients with load. however, cd33 gene transcript expression was increased in load patients compared to controls.