Identification of single-nucleotide and repeat polymorphisms in two candidate genes, interleukin 4 receptor (IL4RA) and signal transducer and activator of transcription protein 6 (STAT6), for Th2-mediated diseases.

We report here the identification of 26 single-nucleotide polymorphisms (SNPs) spanning a total of 147 kb in two candidate genes, IL4RA and STAT6, for atopic disorders. Fourteen novel SNPs were found in our population. We also report the identification of three novel polymorphic (CA) repeat regions in these genes. No insertion/deletion polymorphisms in AluY elements were detected. The encoded proteins of these two genes are part of a single signaling pathway, and therefore, functional polymorphisms in these genes could potentially lead to higher risk and susceptibility to atopic disorders. We also examined the allelic frequency and haplotypes of these polymorphisms in a control population. These data will be potentially useful for association studies designed to investigate the role of these genes in atopic disorders such as asthma, eczema, and allergic rhinitis. This is the first report on the polymorphic content of these two genes in the Indian population.