title: Association between interleukin 6 gene haplotype and Alzheimer's disease: a Brazilian case-control study.
abstract: Alzheimer's disease (AD) is a progressive neurodegenerative disease that takes the form of a local overexpression of cytokines and other inflammatory molecules. We investigated three single-nucleotide polymorphisms (SNP) of the interleukin 6 gene (IL-6) promoter region [-174G/C (rs 1800795), -572C/G (rs 1800796), and -597G/A (rs 1800797)] in 200 patients with late-onset AD and 165 elderly controls in a Brazilian case-control population sample. Genotyping was carried out from blood cells using PCR-RFLP techniques. Statistical analysis was performed to evaluate the Hardy-Weinberg equilibrium and to compare frequencies between groups. No association was found between any IL-6 polymorphism and AD; however the haplotype composed of the -597 A allele and the -174G allele indicated a crude odds ratio (OR) of 0.15 (p = 0.0021) and a significantly adjusted OR (adjusted for the APOE E4 allele value) of 0.15 (p = 0.00294). Linkage disequilibrium was D' = 0.68 among the three SNPs. Our findings revealed a protective effect of AG (-597A, -174G) haplotype, which worked independently of the APOE E4 allele in our Brazilian population sample. Thus, the promoter region of IL-6 gene probably exerts an effect through gene linkage and/or gene interaction.
authors.affiliation: Universidade do Sagrado Coração, Bauru, São Paulo, Brazil.
authors.forename: Lucas
authors.initials: L
authors.lastname: Rasmussen
authors.forename: Roger
authors.initials: R
authors.lastname: Delabio
authors.forename: Lie
authors.initials: L
authors.lastname: Horiguchi
authors.forename: Igor
authors.initials: I
authors.lastname: Mizumoto
authors.forename: Carlos-Renato
authors.initials: CR
authors.lastname: Terazaki
authors.forename: Diego
authors.initials: D
authors.lastname: Mazzotti
authors.forename: Paulo-Henrique
authors.initials: PH
authors.lastname: Bertolucci
authors.forename: Marcela-Augusta
authors.initials: MA
authors.lastname: Pinhel
authors.forename: Dorotéia
authors.initials: D
authors.lastname: Souza
authors.forename: Henrique
authors.initials: H
authors.lastname: Krieger
authors.forename: Carlos
authors.initials: C
authors.lastname: Kawamata
authors.forename: Thais
authors.initials: T
authors.lastname: Minett
authors.forename: Marilia Cardoso
authors.initials: MC
authors.lastname: Smith
authors.forename: Spencer-Luiz
authors.initials: SL
authors.lastname: Payão
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000483:Alleles; D000544:Alzheimer Disease / Q000175:diagnosis / Q000453:epidemiology* / Q000235:genetics*; D001938:Brazil / Q000453:epidemiology; D016022:Case-Control Studies; D005260:Female; D056726:Genetic Association Studies / Q000379:methods*; D006239:Haplotypes / Q000235:genetics*; D006801:Humans; D015850:Interleukin-6 / Q000235:genetics*; D008297:Male; D008875:Middle Aged
chemical_list: C508600:IL6 protein, human; D015850:Interleukin-6