TSHR and autoimmune thyroid disease: Environmental exposures and infections are hypothesised to induce thyroid autoimmunity by ‘molecular mimicry’ (cross-reactivity between microbial antigens or exogenous agents and the TSHR) or ‘bystander activation’ (non-antigen-specific activation of autoreactive lymphocytes), turning a defensive immune response into autoimmunity.9 Environmental factors have also been proposed to trigger thyroid autoimmunity through epigenetic dysregulation modulating gene expression in susceptible individuals.10