Cytokine gene polymorphisms in ischaemic heart disease: investigation using family-based tests of association

Atherosclerosis has an inflammatory basis, with cytokines, cellular adhesion molecules and pro-inflammatory cells having important roles in the initiation and progression of this process. Interleukin (IL) 6, IL-10 and transforming growth factor (TGF) β1 have been proposed as important modulators of the atherosclerotic process, with IL-6 having a pro-inflammatory, atherogenic effect and IL-10 and TGF-β1 having anti-inflammatory, protective roles. The possible role of functional polymorphisms in the promoter regions of the IL-6, IL-10 and TGF-β1 genes in the susceptibility to ischaemic heart disease (IHD) was investigated in a well-defined Irish population using two recently described family-based tests of association. We genotyped 1,012 individuals from 386 families with at least one member prematurely affected with IHD. Using the combined transmission disequilibrium test (TDT)/sib-TDT and the pedigree disequilibrium test, no association between any of the IL-6 −174G/C, IL-10 −1082G/A and TGF-β1 −509C/T polymorphisms and IHD was found. Our data demonstrate that, in an Irish population, these polymorphisms are not associated with IHD.