Polymorphisms of human IL-1b and IL-1 antagonist genes and their informativity for the association studies

Several genetic and immunological studies showed that interleukin-1 (IL-1) is involved in pathogenesis of immune-related disorders e.g. type 1 diabetes, autoimmune thyroiditis or inflammatory bowel disease. Association studies performed till now are rather inconclusive, possibly because investigated markers chosen were not enough informative. The aim of the present study is to elucidate how informative for association screening is the occurrence of known polymorphisms located within genes encoding IL-1β (IL-1B) and IL-1 antagonist (IL-1RN) in Polish population. The following substitutions were analyzed by PCR based techniques: T→C within the promotor region, G→A in intron 4 and C→T in exon 5 of IL-1B gene as well as T→C in exon 2, T→C in exon 4 and the polymorphism of variable number of tandem repeats (VNTR) of 86 base pairs within intron 2 of IL-1RN gene. Obtained results proved the occurrence of all studied polymorphisms in Polish population. Combination of haplotypes related to three novel IL-1B gene dimorphisms reveals that PIC value 0.77 (polymorphic information contents) is similar to that of microsatellite markers. Thus, it is possible that the combination of revealed polymorphisms makes together new marker applicable for the genetic association studies more sensitive then markers previously used.