title: Association between apolipoprotein E polymorphism and Alzheimer disease in Tehran, Iran.
abstract: Epsilon 4 allele of apolipoprotein E (APOE-epsilon4) is a major risk factor for Alzheimer's disease (AD). The association of APOE allele frequencies with AD remains unknown in developing countries. We examined the frequency of APOE alleles in 105 patients with AD and 129 cognitively normal subjects of similar age and sex (control group), in Tehran, Iran. The APOE-epsilon4 allele frequency was significantly higher in the AD subjects than in the control group (21% versus 6.2%, p < 0.001). In addition, the OR for APOE-epsilon4 heterozygous and homozygous subjects were 3.2 (p = 0.001) and 12.75 (p = 0.01), respectively. The OR was not uniform across age groups. The AD subjects carrying one or two APOE-epsilon4 allele showed earlier age-at-onset (p < 0.001). These data suggest that the APOE-epsilon4 allele increase the risk for AD in Tehran population in a dose and age-dependent manner. Although the APOE-epsilon2 allele frequency was lower in the AD subjects than in the control group (0.95% versus 2.7%, p = 0.15), APOE-epsilon2 was not associated with the onset of AD in Tehran's population. The OR for epsilon2 allele in AD subjects was 0.34 (p = 0.21). The genotype frequencies for epsilon3, epsilon4, and epsilon2 alleles in control subjects were 91.2, 6.1, and 2.7%, respectively. These values were similar to that reported for Turkish, Greece, Japanese, Spanish, and Moroccan populations, but they were significantly different from the reported values for the other ethnic populations. This observation emphasizes the importance of geographical location and ethnical background of the subjects in the study of APOE genotypes and their association with AD.
authors.affiliation: Department of Medical Biochemistry, University of Tehran, Tehran, Iran. vaisiraygani@yahoo.com
authors.forename: Asad Vaisi
authors.initials: AV
authors.lastname: Raygani
authors.forename: Mahine
authors.initials: M
authors.lastname: Zahrai
authors.forename: Akbar Vaisi
authors.initials: AV
authors.lastname: Raygani
authors.forename: Mahmood
authors.initials: M
authors.lastname: Doosti
authors.forename: Ebrahim
authors.initials: E
authors.lastname: Javadi
authors.forename: Mansour
authors.initials: M
authors.lastname: Rezaei
authors.forename: Tayebeh
authors.initials: T
authors.lastname: Pourmotabbed
mesh_terms: D017668:Age of Onset; D000368:Aged; D000369:Aged, 80 and over; D000544:Alzheimer Disease / Q000453:epidemiology / Q000235:genetics*; D000704:Analysis of Variance; D053327:Apolipoprotein E4; D001057:Apolipoproteins E / Q000235:genetics*; D016022:Case-Control Studies; D016009:Chi-Square Distribution; D005260:Female; D005787:Gene Frequency; D020022:Genetic Predisposition to Disease; D005838:Genotype; D006801:Humans; D007492:Iran / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D016133:Polymerase Chain Reaction / Q000379:methods; D011110:Polymorphism, Genetic; D044469:Racial Groups / Q000235:genetics; D012737:Sex Factors
chemical_list: D053327:Apolipoprotein E4; D001057:Apolipoproteins E