Autoimmune polyendocrine syndrome type 3

Autoimmune polyendocrine syndrome type 3 is a condition marked by the coexistence of autoimmune thyroiditis with at least one other autoimmune disease, excluding Addison disease, and it results from a combination of genetic and environmental factors that trigger autoimmune attacks on multiple organs. It presents in three recognized subtypes: type 3a pairs thyroid disease with type 1 diabetes, type 3b pairs it with pernicious anemia, and type 3c pairs it with conditions such as alopecia or vitiligo. It affects an estimated 1.4 to 2 people per 100,000, with no particular ethnic predisposition, can begin at any age, and is lifelong, though patients typically have a normal lifespan when the individual autoimmune diseases making up the syndrome are treated.