Cytokine gene polymorphisms of TNFα, IL-6, IL-10, TGFβ and IFNγ in the Saudi population

Abstract

Studies have demonstrated associations between cytokine gene polymorphisms and ethnicity. In the present work the authors examine polymorphisms in the genes encoding interleukin-6 (IL-6), IL-10, interferon-γ (IFNγ), tumour necrosis factor-α (TNFα) and transforming growth factor-(TGFβ1) using the polymerase chain reaction sequence-specific primer (PCR-SSP) method in 150 healthy unrelated Saudis, and results compared with those from other studied populations. The genotype distributions were consistent with the Hardy-Weinberg equilibrium, and the genotype frequencies observed among Saudis showed both similarity and difference to other populations. The most notable difference was in the distribution of IL-6, where the Saudi population showed a lower CG genotype frequency compared with White American (22% vs. 39.2%, P=0.004), Italian (22% vs. 50%, P<0.0001) and Brazilian (22% vs. 40.8%, P<0.0001) populations. The study population also showed a higher frequency of the IL-6 GG genotype compared with White Americans (72% vs. 45.1%, P<0.0001), Italians (72% vs. 41%, P<0.0001) and Brazilians (72% vs. 49.3%, P<0.0001). These results may have significant clinical relevance to the understanding of prevalent diseases in Saudi Arabia.

Key Words:

• Cytokines
• Genotype
• Polymorphism
• genetic