Toxic multinodular goiter is presumed to be autoimmune disorder where thyroid stimulating immunoglobulins bind and activate receptors for thyroid stimulating hormone on the thyroid, whereas in case of solitary toxic nodule the role of iodine deficiency and activating mutations in the thyroid stimulating hormone receptor (TSHr) and Gs alpha gene with consequent marked expression of growth factors and their receptors have been implicated [11]. The gene discussed is TSHR; the disease is autoimmune disease.