Association of IRF 8 gene polymorphisms with autoimmune thyroid disease

Background The occurrence of autoimmune thyroid disease ( AITD ) is known to have a major adverse effect on interferon ( INF )‐α treatment. The genetic variant of the INF regulatory factor 8 ( IRF 8), a type 1 INF regulator, is associated with susceptibility to systemic lupus erythematosus and multiple sclerosis. In this study, we investigated possible associations of the IRF 8 polymorphisms, rs17445836 and rs2280381, with AITD in an ethnic Chinese population. Material and methods In total, 278 patients with Graves' disease ( GD ) and 55 patients with Hashimoto's thyroiditis ( HT ), and 252 healthy controls were enrolled. Polymerase chain reaction‐restriction fragment length polymorphism ( PCR ‐ RFLP ) and direct sequencing were used for genotyping. Results Significantly lower frequencies of the GA genotype and A allele of rs17445836 were found in the HT group than in the control group ( P  =   0·028, odds ratio ( OR ) = 4·71 and P  =   0·022, OR  = 4·40, respectively). Both rs17445836 and rs2280381 were associated with the presence of an antimicrosomal antibody (AmiA), and rs2280381 was also associated with the presence of an antithyroglobulin antibody ( ATA ) in AITD . Moreover, rs17445836 was associated with the level of AmiA in AITD . Conclusions rs17445836 of IRF 8 is a possible genetic variant associated with the development of HT . rs17445836 was associated with the production of thyroid antibody, and the GG genotype of rs17445836 was associated with a higher AmiA titre than the GA genotype.