Polyglandular autoimmune (PGA) syndromes (otherwise known as polyglandular failure syndromes) are constellations of multiple endocrine gland insufficiencies. Other descriptive terminologies, such as autoimmune polyendocrine syndrome (APS), also are used in the literature. In the classification of these syndromes, Roman numerals (eg, I and II) and Arabic numbers (eg, 1 and 2) have been variably used in the literature. For the purpose of consistency in this article, the term PGA and Roman numerals will be used.
Essentially, 2 types of PGA exist, type I and the more common type II, also known as Schmidt syndrome. A third type (type III), which occurs in adults, has been described. Type III does not involve the adrenal cortex, but it includes 2 of the following: thyroid deficiency, pernicious anemia, type 1A diabetes mellitus, vitiligo, and alopecia. Other disorders also have been described in association with the PGA syndromes; pulmonary hypertension in association with PGA syndrome type II (PGA-II) is one example.
Historically, the interest in these syndromes began in the 19th century and essentially focused on the adrenal cortex. In 1849, Thomas Addison first described the clinical and pathologic features of adrenocortical failure in patients who also appeared to have coexisting pernicious anemia. Between 1849 and 1980, geneticists, immunologists, and endocrinologists generated a wealth of new information concerning the pathogenesis of the PGA syndromes and their component disorders.
In 1929, Thorpe and Handley recognized the association of mucocutaneous candidiasis with glandular failure, and case reports and case series have since appeared in the international literature. In 1981, Neufeld and colleagues distinguished 2 major PGA syndromes, and other authors subsequently began to add to our knowledge of these conditions.
In 2004, Eisenbarth and Gottlieb extended the discussion on the classification of these syndromes.
While they acknowledged the system that was adopted by the so-called splitters, dividing the syndromes into 4 subtypes (I, II, III, IV), Eisenbarth and Gottlieb recommended the system adapted by the “lumpers.” The latter system “lumps” the syndromes into just 2 types, I and II. Finally, according to Eisenbarth and Gottlieb, the term polyendocrine is a misnomer, because these syndromes include a number of nonendocrine disorders.
PGA-I, also known as autoimmune polyendocrinopathy-candidiasis-ectodermal dystrophy (APECED) or as Whitaker syndrome, is associated with candidiasis, hypoparathyroidism, and adrenal failure
(although PGA-I without mucocutaneous candidiasis has been reported in an adolescent).
A syndrome with these features was first described in 1946. It is a rare disorder, with sporadic autosomal recessive inheritance.