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AIP-Related Familial Isolated Pituitary Adenomas.


GeneReviews® [Internet]. Seattle (WA): University of Washington, Seattle; 1993-2019.
2012 Jun 21.

Author information

Department of Endocrinology, Barts and the London School of Medicine, Queen Mary University of London, London, United Kingdom
Clinical Genetics Unit, North East Thames Regional Genetics Service, Great Ormond Street Hospital, London, United Kingdom



AIP-related isolated familial pituitary adenoma (AIP-related FIPA) is defined as the presence of an AIP germline pathogenic variant in an individual with a pituitary adenoma (regardless of family history). The most commonly occurring pituitary adenomas in this disorder are growth hormone-secreting adenomas (somatotropinoma), followed by prolactin-secreting adenomas (prolactinoma), growth hormone and prolactin co-secreting adenomas (somatomammotropinoma), and non-functioning pituitary adenomas (NFPA). Rarely TSH- or ACTH-secreting adenomas (thyrotropinoma and corticotropinoma) are observed. Clinical findings result from excess hormone secretion, lack of hormone secretion, and/or mass effects (e.g., headaches, visual field loss). Within the same family, pituitary adenomas can be of the same or different type. Age of onset in AIP-related FIPA is around 20-24 years (age range: 6-66 years).


The diagnosis of AIP-related FIPA relies on identification of characteristic pituitary adenomas based on hormone secretion, pituitary MRI, and histologic findings, and identification of a heterozygous AIP pathogenic variant in an affected family member.


Treatment of manifestations: Pituitary adenomas identified in those with AIP-related FIPA are treated in the same manner as pituitary adenomas of unknown cause: they can be treated by surgery, medical therapy (somatostatin analogs, growth hormone receptor antagonists, and dopamine agonists), and/or radiotherapy. Although surgery is usually performed in persons with AIP-related FIPA, it often does not fully control the tumor; thus, medical therapy and radiotherapy following surgery may be required to control hormone output and tumor growth. Surveillance: Persons with AIP-related FIPA who have had a pituitary adenoma need to be followed for both recurrence of a treated adenoma and development of new adenomas. No specific guidelines exist; the authors' recommendations are: Yearly clinical assessment and pituitary function tests (IGF-1, spot GH, prolactin, LH/FSH, estradiol/testosterone, TSH, fT4, and morning cortisol); Dynamic testing to evaluate for hormone excess or deficiency (e.g., glucose tolerance test, insulin tolerance test) as needed; and Follow-up pituitary MRI, with frequency depending on clinical status, previous extent of the tumor, and treatment modality. Clinical monitoring of secondary complications of the tumor and/or its treatment (e.g., diabetes mellitus, hypertension, osteoarthritis, hypogonadism, osteoporosis) are necessary. Evaluation of relatives at risk: Family members at risk for AIP-related FIPA warrant molecular genetic testing for the family-specific pathogenic variant to identify those who harbor the variant and thus require surveillance over time for pituitary adenomas.


AIP-related FIPA is inherited in an autosomal dominant manner. Each child of an individual with AIP-related FIPA has a 50% chance of inheriting the pathogenic variant. Prenatal diagnosis for pregnancies at increased risk is possible if the AIP pathogenic variant of an affected family member has been identified; however, requests for prenatal testing for conditions which (like FIPA) do not affect intellect and have some treatment available are rare. Furthermore, as AIP-related FIPA demonstrates reduced penetrance, the finding of a AIP pathogenic variant prenatally does not allow accurate prediction of whether a tumor will develop, the adenoma type, age of onset, prognosis, availability of and/or outcome of treatment.

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