Analysis of genetic polymorphisms in the transforming growth factor-beta1 gene and the risk of Alzheimer's disease

Hum Genet. 2000 May;106(5):565-9. doi: 10.1007/s004390000313.


Alzheimer's disease (AD) is a complex disease involving several genetic and environmental components. Genetic studies have yet to identify all the genes involved in the pathogenesis of AD. Transforming growth factor-beta1 (TGF-beta1) is a candidate gene for AD. It is a multifunctional cytokine whose overexpression has been shown to promote the deposition of amyloid-beta peptide. The goal of this study was to investigate the association of three polymorphisms in TGF-beta1 with the risk of AD. Two of the polymorphisms are located in the 5' region at positions -800 (G-->A) and -509 (C-->T), and the third is in exon 5 at codon 263 (Thr-->Ile). We screened DNA samples from 428 sporadic, late-onset patients and 421 controls by PCR-based assays. There was no statistically significant difference in genotype or allele frequency distributions between cases and controls for the -800 or codon 263 polymorphisms (P=0.38 and P=0.60, respectively). The overall genotype distribution at the -509 site was significantly different between cases and controls. (P=0.017). The frequency of the -509/TT genotype was significantly higher in AD patients than controls (P=0.015). We further tested whether this polymorphism may alter the regulation of the TGF-beta1 gene using dual luciferase reporter assay. We subcloned the 5' flanking region, which contained the -509 C/T polymorphic sites, in front of the firefly luciferase reporter gene in pGL-3 basic vector and co-transfected with the pRL-CMV vector containing Renilla luciferase gene as a control for transfection efficiency in COS-1 cells. The activity of each promoter allele was directly measured by the ratio of firefly luciferase activity to Renilla luciferase activity. The -509 T allele was associated with marginally higher transcriptional activity of TGF-beta compared with the -509 C allele (P=0.051). These data suggest that the -509 polymorphism of TGF-beta1 may be modestly associated with the risk of AD. However, these data should be interpreted with caution as the differences associated with the -509 alleles in both the genetic association and the transfection studies were modest.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Aged
  • Aged, 80 and over
  • Alleles
  • Alzheimer Disease / etiology
  • Alzheimer Disease / genetics*
  • Alzheimer Disease / immunology
  • Animals
  • Base Sequence
  • COS Cells
  • DNA Primers / genetics
  • Female
  • Gene Frequency
  • Genes, Reporter
  • Humans
  • Luciferases / genetics
  • Male
  • Middle Aged
  • Polymorphism, Genetic*
  • Promoter Regions, Genetic
  • Risk Factors
  • Transfection
  • Transforming Growth Factor beta / genetics*


  • DNA Primers
  • Transforming Growth Factor beta
  • Luciferases