Association analysis of monocyte chemotactic protein-3 (MCP3) polymorphisms with asthmatic phenotypes

The monocyte chemotactic protein-3 (MCP3), on chromosome 17q11.2-q12, is a secreted chemokine, which attracts macrophages during inflammation and metastasis. In an effort to discover additional polymorphism(s) in genes whose variant(s) have been implicated in asthma, we scrutinized the genetic polymorphisms in MCP3 to evaluate it as a potential candidate gene for asthma host genetic study. By direct DNA sequencing in twenty-four individuals, we identified four sequence variants within the 3 kb full genome including 1,000bp promoter region of MCP3; one in promoter region (-420T>C), three in intron (+136C>G, +563C>T, +984G>A) respectively. The frequencies of those four SNPs were 0.020 (-420T>C), 0.038 (+136C>G), 0.080 (+563C>T), 0.035 (+984G>A), respectively, in Korean population (n = 598). Haplotypes, their frequencies and linkage disequilibrium coefficients (|D'|) between SNP pairs were estimated. The associations with the risk of asthma, skin-test reactivity and total serum IgE levels were analyzed. Using statistical analyses for association of MCP3 polymorphisms with asthma development and asthma-related phenotypes, no significant signals were detected. In conclusion, we identified four genetic polymorphisms in the important MCP3 gene, but no significant associations of MCP3 variants with asthma phenotypes were detected. MCP3 variation/haplotype information identified in this study will provide valuable information for future association studies of other allergic diseases.