Autoimmune polyglandular syndromes are rare diseases characterized by autoimmune activity against more than one endocrine organ. There are three main classifications: type 1 is autosomal recessive and involves hypoparathyroidism, adrenal insufficiency, and others; type 2 is autosomal dominant and involves adrenal insufficiency plus hypothyroidism or diabetes; IPEX syndrome is X-linked and affects males, causing diabetes and diarrhea. Each type has a different genetic cause, and diagnosis involves endoscopic tests, CT scans, or histology. Treatment depends on the type but may include immunosuppressive therapy, ketoconazole, or managing the individual diseases.