Genome-wide association study for pollinosis identified two novel loci in interleukin (IL)-1B in a Japanese population

The number of pollinosis patients in Japan has significantly increased over the past 20 years. The majority of genome-wide association studies (GWAS) on pollinosis have been conducted in subjects of European descent, with few studies in Japanese populations. The aim of our GWAS was to identify genetic loci associated with self-reported pollinosis in a Japanese population and to understand its molecular background using a combination of single nucleotide polymorphisms (SNPs) and gene- and pathway-based analyses. A total of 731 and 560 individuals who were recruited as participants of the Japan Multi-Institutional Collaborative Cohort Study participated in the discovery and replication phases, respectively. The phenotype of pollinosis was based on the information from a self-administered questionnaire. In the single-SNP analysis, four SNPs (rs11975199, rs11979076, rs11979422, and rs12669708) reached suggestive significance level (P < 1 x 10(-4)) and had effects in the same direction in both phases of the study. The pathway-based analysis identified two suggestive pathways (nucleotide-binding oligomerization domain -like receptor and tumor necrosis factor signaling pathways). Both rs1143633 and rs3917368 in the interleukin-1B gene showed associations in the retrace (from pathway to gene and SNP) analysis. We performed single-SNP, gene, and pathway analysis and shed light on the molecular mechanisms underlying pollinosis in a Japanese population.