Autoimmune polyendocrinopathy-candidiasis-ectodermal dystrophy

Autoimmune polyendocrinopathy-candidiasis-ectodermal dystrophy (APECED) is an inherited condition that affects many of the body's organs. It is one of many autoimmune diseases, which are disorders that occur when the immune system malfunctions and attacks the body's own tissues and organs by mistake.

In most cases, the signs and symptoms of APECED begin in childhood or adolescence. This condition commonly involves three characteristic features: chronic mucocutaneous candidiasis (CMC), hypoparathyroidism, and adrenal gland insufficiency. Affected individuals typically have at least two of these features, and many have all three.

CMC is a tendency to develop infections of the skin, the nails, and the moist lining of body cavities (mucous membranes) caused by a type of fungus called Candida. These infections, which are commonly known as yeast infections, are chronic, which means they recur and can last a long time. CMC is usually the first of the three characteristic features of APECED to become apparent in people with this disorder. Almost all affected individuals develop infections of the oral cavity (known as thrush). Infections of the tube that carries food from the mouth to the stomach (the esophagus) are also common, while the skin and nails are affected less often. In women, vaginal infections frequently occur.

Other features of APECED result from the body's immune system attacking the network of hormone-producing glands (the endocrine system). The second characteristic feature of the disorder is hypoparathyroidism, which is a malfunction of the parathyroid glands. These glands secrete a hormone that regulates the body's use of calcium and phosphorus. Damage to the parathyroid glands leads to reduced parathyroid hormone production (hypoparathyroidism). Hypoparathyroidism can cause a tingling sensation in the lips, fingers, and toes; muscle pain and cramping; weakness; and fatigue. Serious effects of hypoparathyroidism, such spasms of the voicebox (larynx) leading to breathing problems and seizures, can be life-threatening.

Damage to the small hormone-producing glands on top of each kidney (adrenal glands) results in a third major feature of APECED, adrenal gland insufficiency (autoimmune Addison disease). Reduced hormone production by the adrenal glands leads to signs and symptoms that can include fatigue, muscle weakness, loss of appetite, weight loss, low blood pressure, and changes in skin coloring. Other endocrine problems that can occur in APECED include type 1 diabetes resulting from impaired production of the hormone insulin; a shortage of growth hormone leading to short stature; problems affecting the internal reproductive organs (ovaries or testes) that can cause inability to conceive children (infertility); and dysfunction of the thyroid gland (a butterfly-shaped tissue in the lower neck), which can result in many symptoms including weight gain and fatigue.

Autoimmune problems affecting non-endocrine tissues can lead to a variety of additional signs and symptoms in people with APECED. These features occur more often in North American populations than in European populations. Rashes that resemble hives (urticarial eruptions) are common and often occur in infancy and early childhood. Other early signs and symptoms may include thin enamel on the teeth (enamel hypoplasia) and chronic diarrhea or constipation associated with difficulty in absorbing nutrients from food. Additional features that occur in people with APECED, many of which can lead to permanent organ and tissue damage if left untreated, include stomach irritation (gastritis), liver inflammation (hepatitis), lung irritation (pneumonitis), dry mouth and dry eyes (Sjogren-like syndrome), inflammation of the eyes (keratitis), kidney problems (nephritis), vitamin B12 deficiency, hair loss (alopecia), loss of skin color in blotches (vitiligo), high blood pressure (hypertension), or a small (atrophic) or absent spleen (asplenia).

APECED occurs in about 1 in 90,000 to 200,000 people in most populations studied, which have been mainly in Europe. This condition occurs more frequently in certain populations, affecting about 1 in 9,000 to 25,000 people among Iranian Jews, Sardinians, and Finns.

Mutations in the AIRE gene cause APECED. The AIRE gene provides instructions for making a protein called the autoimmune regulator. As its name suggests, this protein plays a critical role in regulating certain aspects of immune system function. Specifically, it helps the body distinguish its own proteins and cells from those of foreign invaders (such as bacteria, fungi, and viruses). This distinction is critical because to remain healthy, a person's immune system must be able to identify and destroy potentially harmful invaders while sparing the body's normal tissues.

Mutations in the AIRE gene reduce or eliminate the function of the autoimmune regulator protein. Without enough of this protein function, the immune system's ability to distinguish between the body's proteins and foreign invaders is impaired, and it may attack the body's own organs. This reaction, which is known as autoimmunity, results in inflammation and can damage otherwise healthy cells and tissues. Autoimmune damage to the adrenal glands, parathyroid glands, and other organs underlies many of the major features of APECED.

Studies suggest that AIRE gene mutations also result in immune substances (antibodies) mistakenly attacking proteins involved in an immune process called the IL-17 pathway, which is important in the body's defense against Candida. This pathway, which depends on specialized proteins called IL-17 cytokines for signaling, creates inflammation, sending additional cytokines and white blood cells to fight foreign invaders and promote tissue repair. In addition, the IL-17 pathway promotes the production of certain antimicrobial protein segments (peptides) that control growth of Candida on the surface of mucous membranes. By damaging IL-17 cytokines, AIRE gene mutations are thought to impair the IL-17 pathway's function, resulting in CMC in people with APECED.

Researchers believe that differences in the effects of specific AIRE gene mutations as well as variations in other genes that have not been identified may help explain why the signs and symptoms of APECED can vary among affected individuals and populations.

Genetic Testing Information

• Genetic Testing Registry: Autoimmune polyglandular syndrome type 1, with reversible metaphyseal dysplasia
• Genetic Testing Registry: Polyglandular autoimmune syndrome, type 1

Genetic and Rare Diseases Information Center

• Autoimmune polyendocrinopathy type 1

Patient Support and Advocacy Resources

• National Organization for Rare Disorders (NORD)

Clinical Trials

• ClinicalTrials.gov

Catalog of Genes and Diseases from OMIM

• AUTOIMMUNE POLYENDOCRINE SYNDROME, TYPE I, WITH OR WITHOUT REVERSIBLE METAPHYSEAL DYSPLASIA; APS1

Scientific Articles on PubMed

• PubMed

• Constantine GM, Lionakis MS. Lessons from primary immunodeficiencies: Autoimmune regulator and autoimmune polyendocrinopathy-candidiasis-ectodermal dystrophy. Immunol Rev. 2019 Jan;287(1):103-120. doi: 10.1111/imr.12714. Citation on PubMed or Free article on PubMed Central
• De Martino L, Capalbo D, Improda N, D'Elia F, Di Mase R, D'Assante R, D'Acunzo I, Pignata C, Salerno M. APECED: A Paradigm of Complex Interactions between Genetic Background and Susceptibility Factors. Front Immunol. 2013 Oct 23;4:331. doi: 10.3389/fimmu.2013.00331. Citation on PubMed or Free article on PubMed Central
• De Martino L, Capalbo D, Improda N, Lorello P, Ungaro C, Di Mase R, Cirillo E, Pignata C, Salerno M. Novel Findings into AIRE Genetics and Functioning: Clinical Implications. Front Pediatr. 2016 Aug 22;4:86. doi: 10.3389/fped.2016.00086. eCollection 2016. Citation on PubMed or Free article on PubMed Central
• DeVoss JJ, Anderson MS. Lessons on immune tolerance from the monogenic disease APS1. Curr Opin Genet Dev. 2007 Jun;17(3):193-200. doi: 10.1016/j.gde.2007.04.001. Epub 2007 Apr 26. Citation on PubMed
• Ferre EM, Rose SR, Rosenzweig SD, Burbelo PD, Romito KR, Niemela JE, Rosen LB, Break TJ, Gu W, Hunsberger S, Browne SK, Hsu AP, Rampertaap S, Swamydas M, Collar AL, Kong HH, Lee CR, Chascsa D, Simcox T, Pham A, Bondici A, Natarajan M, Monsale J, Kleiner DE, Quezado M, Alevizos I, Moutsopoulos NM, Yockey L, Frein C, Soldatos A, Calvo KR, Adjemian J, Similuk MN, Lang DM, Stone KD, Uzel G, Kopp JB, Bishop RJ, Holland SM, Olivier KN, Fleisher TA, Heller T, Winer KK, Lionakis MS. Redefined clinical features and diagnostic criteria in autoimmune polyendocrinopathy-candidiasis-ectodermal dystrophy. JCI Insight. 2016 Aug 18;1(13):e88782. doi: 10.1172/jci.insight.88782. Citation on PubMed or Free article on PubMed Central
• Gallo V, Giardino G, Capalbo D, Palamaro L, Romano R, Santamaria F, Maio F, Salerno M, Vajro P, Pignata C. Alterations of the autoimmune regulator transcription factor and failure of central tolerance: APECED as a model. Expert Rev Clin Immunol. 2013 Jan;9(1):43-51. doi: 10.1586/eci.12.88. Citation on PubMed
• Kisand K, Boe Wolff AS, Podkrajsek KT, Tserel L, Link M, Kisand KV, Ersvaer E, Perheentupa J, Erichsen MM, Bratanic N, Meloni A, Cetani F, Perniola R, Ergun-Longmire B, Maclaren N, Krohn KJ, Pura M, Schalke B, Strobel P, Leite MI, Battelino T, Husebye ES, Peterson P, Willcox N, Meager A. Chronic mucocutaneous candidiasis in APECED or thymoma patients correlates with autoimmunity to Th17-associated cytokines. J Exp Med. 2010 Feb 15;207(2):299-308. doi: 10.1084/jem.20091669. Epub 2010 Feb 1. Citation on PubMed or Free article on PubMed Central
• Kisand K, Peterson P. Autoimmune polyendocrinopathy candidiasis ectodermal dystrophy and other primary immunodeficiency diseases help to resolve the nature of protective immunity against chronic mucocutaneous candidiasis. Curr Opin Pediatr. 2013 Dec;25(6):715-21. doi: 10.1097/MOP.0000000000000028. Citation on PubMed
• Kisand K, Peterson P. Autoimmune polyendocrinopathy candidiasis ectodermal dystrophy. J Clin Immunol. 2015 Jul;35(5):463-78. doi: 10.1007/s10875-015-0176-y. Epub 2015 Jul 5. Citation on PubMed
• Oftedal BE, Hellesen A, Erichsen MM, Bratland E, Vardi A, Perheentupa J, Kemp EH, Fiskerstrand T, Viken MK, Weetman AP, Fleishman SJ, Banka S, Newman WG, Sewell WA, Sozaeva LS, Zayats T, Haugarvoll K, Orlova EM, Haavik J, Johansson S, Knappskog PM, Lovas K, Wolff AS, Abramson J, Husebye ES. Dominant Mutations in the Autoimmune Regulator AIRE Are Associated with Common Organ-Specific Autoimmune Diseases. Immunity. 2015 Jun 16;42(6):1185-96. doi: 10.1016/j.immuni.2015.04.021. Citation on PubMed
• Puel A, Doffinger R, Natividad A, Chrabieh M, Barcenas-Morales G, Picard C, Cobat A, Ouachee-Chardin M, Toulon A, Bustamante J, Al-Muhsen S, Al-Owain M, Arkwright PD, Costigan C, McConnell V, Cant AJ, Abinun M, Polak M, Bougneres PF, Kumararatne D, Marodi L, Nahum A, Roifman C, Blanche S, Fischer A, Bodemer C, Abel L, Lilic D, Casanova JL. Autoantibodies against IL-17A, IL-17F, and IL-22 in patients with chronic mucocutaneous candidiasis and autoimmune polyendocrine syndrome type I. J Exp Med. 2010 Feb 15;207(2):291-7. doi: 10.1084/jem.20091983. Epub 2010 Feb 1. Citation on PubMed or Free article on PubMed Central