Association between interferon‐induced helicase ( IFIH1 IFIH1 IFIH1 ) rs1990760 polymorphism and seasonal variation in the onset of type 1 diabetes mellitus

摘要

Background Infections, mostly of viral origin, may contribute to the seasonal variation in the onset of type 1 diabetes mellitus ( T1DM ). The rs1990760 (AG, Ala946Thr ) polymorphism ( GG genotype) of the interferon induced helicase ( IFIH1 ), a virus recognition receptor, confers a modest protection for T1DM . The aim of our study was to evaluate a possible association between this IFIH1 polymorphism and the seasonal variation in the onset of T1DM . Materials and Methods The IFIH1 rs1990760 polymorphism was genotyped in 1055 patients of Central‐Eastern European ancestry with T1DM (median age at diagnosis: 8.2 [interquartile range, IQR 4.8‐11.8] years). T1DM onset was recorded in monthly intervals. Results The IFIH1 genotype distribution was the following: 436 patients (41.3%) had AA genotype, 483 patients (45.8%) had AG genotype, and 136 patients (12.9%) had GG genotype. Significant seasonal variation in manifestation of T1DM (highest rate in winter and lowest rate in summer period) was observed in the total cohort ( n = 1055), irrespective of gender. The disease predisposing AA genotype was more frequently found among new cases with onset in summer vs in those with onset in winter (44.3% vs 37.9%); conversely, the protective GG genotype was less frequent (9.3% vs 12.9%, respectively; P = .0268 for trend). Significant effect of genotype ( P = .0418) was found on the seasonal variability of T1DM onset in the total cohort. Conclusions The IFIH1 rs1990760 polymorphism seems to be associated with the seasonal manifestation of T1DM . Our findings suggest that this virus receptor gene may contribute to T1DM manifestation primarily in the summer period.