Autoimmune polyendocrine syndrome multiple

A rare disorder characterized by the presence of multiple autoimmune diseases affecting endocrine glands.

Autoimmune polyendocrine syndrome multiple (APS) is a rare, complex disorder characterized by the coexistence of multiple autoimmune diseases that affect the endocrine system. These syndromes are also known as polyglandular autoimmune syndromes (PAS) and are classified into different types based on the specific combination of diseases present.

Classification

APS is generally classified into three main types:

Type 1 (APS-1)

APS-1, also known as autoimmune polyendocrinopathy-candidiasis-ectodermal dystrophy (APECED), is a rare genetic disorder caused by mutations in the AIRE gene. It typically presents in childhood and is characterized by the triad of:

• Chronic mucocutaneous candidiasis
• Hypoparathyroidism
• Adrenal insufficiency (Addison's disease)

Type 2 (APS-2)

APS-2 is more common than APS-1 and usually presents in adulthood. It is characterized by the presence of:

• Adrenal insufficiency
• Autoimmune thyroid disease (such as Hashimoto's thyroiditis or Graves' disease)
• Type 1 diabetes mellitus

Type 3 (APS-3)

APS-3 is characterized by the presence of autoimmune thyroid disease along with other autoimmune conditions, excluding adrenal insufficiency. It is further subdivided into:

• APS-3A: Autoimmune thyroid disease with Type 1 diabetes mellitus
• APS-3B: Autoimmune thyroid disease with Pernicious anemia
• APS-3C: Autoimmune thyroid disease with Vitiligo

Pathophysiology

The pathophysiology of APS involves a complex interplay of genetic, environmental, and immunological factors. The presence of autoantibodies against various endocrine tissues leads to the destruction and dysfunction of these glands. In APS-1, mutations in the AIRE gene result in a failure of central tolerance, allowing autoreactive T cells to escape into the periphery. In APS-2 and APS-3, the exact mechanisms are less well understood but are believed to involve a combination of genetic predisposition and environmental triggers.

Diagnosis

Diagnosis of APS is based on clinical criteria, the presence of specific autoantibodies, and genetic testing, particularly for APS-1. Endocrine function tests are used to assess the involvement of specific glands. For example, the ACTH stimulation test is used to diagnose adrenal insufficiency, while thyroid function tests are used to diagnose autoimmune thyroid disease.

Management

Management of APS involves treating the individual autoimmune conditions present. This may include hormone replacement therapy, such as glucocorticoids for adrenal insufficiency, levothyroxine for hypothyroidism, and insulin for type 1 diabetes. Regular monitoring and a multidisciplinary approach are essential to manage the complex needs of patients with APS.

Prognosis

The prognosis of APS varies depending on the specific type and the combination of autoimmune diseases present. Early diagnosis and appropriate management can improve outcomes and quality of life for affected individuals.

Also see

• Autoimmune disease
• Endocrine system
• Adrenal insufficiency
• Autoimmune thyroid disease
• Type 1 diabetes mellitus