A comparative search for human FceRIa gene (FCER1A) 30-UTR polymorphisms in Japanese and Polish populations

The high affinity immunoglobulinE(IgE) receptor (FceRI) plays a key role in the pathogenesis of atopy and allergic disorders. Several polymorphisms located in 50-flanking region and 5'-untranslated region (5'-UTR) of human FCER1A, the gene encoding FceRI a-subunit, have been shown to functionally affect its transcriptional activity. All those genetic variants have been also associatedwith allergic diseases and/or serum IgE levels. In the present study, we sought to identify functional polymorphisms in human FCER1A 30-untranslated region (3'-UTR), the potential candidates for future genetic association studies. Search for polymorphisms within human FCER1A 30-UTR region, conducted in Japanese and Poles, revealed the presence of +565'A>G and +5714G>A variants. Subsequently, structure/distribution of haplotypes and LD measures were analyzed in Japanese and Poles for both 30-UTR variants and the functional polymorphisms located in 5'-flanking region and 5'-UTR of human FCER1A. Additionally, reporter plasmids containing human FCER1A main promoter and 30-UTR with all four possible combinations of+5650A>G and+5714G>A polymorphisms were constructed to evaluate functional potential of both 30-UTR variants. However, no genotype-related differences in the gene expression were observed, as measured by reporter activity in cultured human basophil/mast cell-like KU812 cells, suggesting that both +565'A>G and +5714G>A have no genotype-related functional effect. In summary, we described linkage disequilibrium and the distribution of haplotypes for two identified human FCER1A 30-UTR polymorphisms and several previously reported 5'-flanking region and 50-UTR variants in Japanese and Poles, representative for East Asians and Caucasians, the two ethnic groups in which genetic associations between FCER1A and allergic diseases and/or serum IgE levels have been previously reported.