Polymorphisms in TSHR and IL1RN genes and the risk and prognosis of Graves’ disease in Tunisian population

Graves’ disease (GD) is a complex genetic autoimmune thyroid diseases (AITD). TSHR is considered as candidate gene in GD. IL1RN gene shown to be related to the pathogenesis of a number of autoimmune diseases. These finding prompted us to investigate the association of TSHR and IL1RN genes polymorphism with the risk and the prognosis of GD in Tunisia. A total of 249 healthy controls and 68 GD patients were genotyped for TSHR D727E and IL1RN polymorphism. No significant difference was found for D727E polymorphism between GD patients and healthy controls. For IL1RN, we found an association between GD and IL1RN A1A2 genotype. TSHR polymorphism was associated with GD susceptibility in patients older than 40 years. We found for the first time an association of IL1RN polymorphism with the production of anti-thyroglobulin and anti-thyroid peroxidase antibody at the onset of disease. These preliminary results suggest that TSHR polymorphism may be a risk factor for late onset of GD, and that IL1RN polymorphism may be associated with GD susceptibility and may represent prognostic factor for predicting the severity of GD.