In addition to type 1 diabetes, two patients also developed autoimmune thyroiditis (AT, autoimmune polyglandular syndrome Type 3 variant, APS3v); one of the two was affected by Hashimoto’s thyroiditis confirmed by the presence of circulating Tg and TPO AAbs and echography pattern of diffuse hypoechogenicity. The gene discussed is TG; the disease is Hashimoto thyroiditis.