Characterization of polymorphisms of an interleukin 1 receptor type 1 gene (IL1RI) promotor region (P2) and their relation to Insulin-Dependent Diabetes Mellitus (IDDM)

Abstract

We have identified two PstI polymorphisms of the interleukin 1 receptor type I gene (IL1RI). One of these (RFLP-A) showed significant association to IDDM (P=0.027), whereas no difference between patients and control subjects was found for RFLP-B (P=0.42). RFLP-A was physically mapped to the 5 ′UTR of the gene. We sequenced and analysed a 411 bp region of a putative promotor region (P2) around RFLP-A. RFLP-A was due to a C to T transition in exon 1B of theIL1RIgene. This single-base mutation did not affect any known transcription factor recognition sequence or the predicted secondary mRNA structure. In addition, we found two other single-base substitutions in more than one individual. Neither of these showed specific disease association or absolute linkage with the RFLP-A.