Definition:

Acromegaly (ACM) is a disorder characterized by increased circulating GH and IGF-I (a GH-induced liver protein) levels that is associated with significant morbidity and excess mortality. Patients with persistently elevated GH and IGF-I levels have an increased risk of multiple comorbidities, including left ventricular dysfunction, obstructive sleep apnea, arthritis, impaired glucose tolerance, and colonic polyps. Most cases of ACM occur as a result of a sporadic GH-secreting pituitary adenoma (PA). However, ACM can occur in a familial setting, either associated with other endocrine abnormalities or as an isolated disorder. Somatic activating mutations in the GNAS gene, which encodes for the Gs-alpha subunit of G-proteins, are found in up to 40% of sporadic GH-secreting PA. Familial ACM can occur in the context of rare inherited syndromes such as familial isolated pituitary adenoma (FIPA), which is caused in 15-20% of cases by aryl hydrocarbon receptor interacting protein (AIP) gene germline mutations. Moreover, a recurrent mutation was found in GPR101 in some patients with non-familial ACM.