Autoimmune polyendocrine syndrome type II, also known as Schmidt syndrome, is a rare autoimmune disorder in which there is a steep drop in production of several essential hormones by the glands that secrete these hormones. When first described, this disorder was thought to involve only adrenal insufficiency (Addison's disease) and thyroid insufficiency (Hashimoto's thyroiditis). However, over time, as more patients were studied, the scope of the disorder was expanded to include disorders of other underperforming endocrine glands. These include the gonads, which secrete sex hormones; the pancreas which secretes insulin and is intimately tied up with diabetes mellitus; and sometimes the parathyroid glands. Failure of the endocrine glands to function is usually accompanied by signs of malnutrition because the ability of the intestinal tract to absorb nutrients is reduced dramatically. Since the combination of affected glands differs from patient to patient, the signs of this disorder are diverse.
Most cases of this disorder are sporadic although some clinical researchers believe that there is a familial or hereditary trait associated with AIPS-II. If so, it may involve a complex interaction among many genes.