Chapter 21 - Genetics of Pituitary Tumor Syndromes

Abstract

Pituitary adenomas are a heterogeneous group of tumors with distinctive secretory and growth characteristics, and the molecular pathophysiology of sporadic adenomas is mostly unclear. Approximately 5% of pituitary adenomas occur in the setting of an inherited or familial condition and these tumors may exhibit more aggressive characteristics. Pituitary adenomas can occur as part of syndromic neoplasia disorders, such as multiple endocrine neoplasia type 1 (MEN1), and Carney complex. The most frequent familial clinical presentation of pituitary adenomas is as familial isolated pituitary adenomas (FIPAs), of which 15–20% are caused by mutations of the aryl hydrocarbon-receptor interacting protein (AIP) gene. Genetic forms of pituitary adenomas account for an important proportion of pituitary adenomas that occur in children and adolescents, and nearly 50% of pituitary gigantism patients have a genetic cause, including AIP, X-linked acrogigantism, and McCune–Albright syndrome. Knowledge of the clinical features of genetically determined pituitary adenomas can help guide genetic testing strategies and optimize the diagnosis and follow-up of mutation carriers.