**3.1 Toxic MNG**

Toxic MNG is a result of activating somatic mutation of the TSH receptor gene that leads to diffuse hyperplasia of thyroid follicular cells independent of TSH regulation [14–16]. MNG with thyrotoxicosis is also known as Plummer's disease. Toxic MNG presented with clinical features similar to other causes of thyrotoxicosis except ophthalmopathy. Incidence of thyrotoxicosis in MNG is related to the duration of the presence of MNG. So it's more common in elderly people who are harboring MNG for a long time. Hormone profile in toxic MNG is seen with suppressed TSH along with normal or elevated thyroid hormones.
