**3.6 Infiltrative thyroid disorder**

Various infiltrative disorders like amyloidosis, histiocytosis, cystinosis and sarcoidosis may affect thyroid gland.

## **3.7 Graves' disease**

This autoimmune condition is characterized by presence of TRAB (TSH receptor autoantibodies) in the serum. The clinical feature ranges from hyperthyroidism, orbitopathy, dermopathy and goiter.
