Polyglandular Syndrome Type III (also known as Schmidt's Syndrome) is an autoimmune disorder, characterized by the presence of multiple autoimmune diseases in one individual. It is typically caused by an inherited gene mutation, and is associated with an increased risk of developing autoimmune diseases such as type 1 diabetes, Hashimoto's thyroiditis, Addison's disease, vitiligo, alopecia areata, and pernicious anemia. Symptoms of the disorder can vary, depending on which autoimmune diseases are present, but often include fatigue, muscle weakness, weight loss, and irregular blood sugar levels. Treatment of Schmidt's Syndrome typically involves managing the individual autoimmune diseases, and controlling symptoms with medications, lifestyle changes, and immunosuppressants.