Evaluation of the impact of polymorphisms on candidate genes of allergic rhinitis and asthma on disease outcomes in the Singapore population

Abstract

This study aimed to investigate the association between the candidate gene polymorphisms and atopic phenotypes in Singapore population. The following polymorphisms of candidate genes, including CD14 (-159, -550, -1145, and -1359), IL-4 (-590), IL-18 (-137, +113 and +127), I?2-adrenergic receptor (B2AR) (Arg16Gly and Gln27Glu) and Toll-like receptor 4 (TLR-4) (Asp299Gly and Thr399Ile) were genotyped using direct PCR-sequencing or RFLP methods in Singaporean Chinese (n=331), Malays (n=51) and Asian Indians (n=101). Furthermore, the polymorphisms of CD14 promoter and IL-18 5a?? non-trancription region were investigated by reporter assay in different cell-lines (THP-1, U937, HepG2 and HeLa). The results of this study are not completely consistent with some literature reports in other ethnic populations. However, it confirms that predisposition to atopy is influenced by complex immune processes, including interaction of multiple genes, interaction of environmental and genetic factors, and population heterogeneity.