From OMIM
Mutations in the AIP gene have been found predominantly in growth hormone (GH)-secreting adenomas, but have also been found in adrenocorticotropic hormone (ACTH)-secreting, thyroid hormone (TSH)-secreting, and prolactin (PRL)-secreting pituitary tumors. Pituitary adenomas are benign monoclonal neoplasms of the anterior pituitary gland, accounting for approximately 15% of intracranial tumors. Growth hormone (139250)-secreting adenomas, also known as somatotropinomas, which clinically result in acromegaly, comprise about 20% of all pituitary tumors and are the second most common hormone-secreting pituitary tumor after prolactin (176760)-secreting tumors, which account for 40 to 45% of pituitary tumors. ACTH-secreting tumors, which result in Cushing disease, and thyrotropin (TSHB; 188540)-secreting tumors are much less common. Nonsecreting pituitary tumors, which account for about 33%, can cause symptoms due to local compressive effects of tumor growth (Vierimaa et al., 2006; Georgitsi et al., 2007; Horvath and Stratakis, 2008). Acromegaly is characterized by coarse facial features, protruding jaw, and enlarged extremities (Vierimaa et al., 2006). Familial isolated somatotropinoma (FIS) is defined as the occurrence of at least 2 cases of acromegaly or gigantism in a family that does not exhibit features of other endocrine syndromes. FIS patients tend to have onset about 4 to 10 years earlier than patients with sporadic disease (Gadelha et al., 1999; Horvath and Stratakis, 2008). Cushing disease is characterized by central obesity, moon facies, diabetes, 'buffalo hump,' hypertension, fatigue, easy bruising, depression, and reproductive disorders. Cushing disease is associated with increased morbidity and mortality, mainly due to cardiovascular or cerebrovascular disease and infections (summary by Perez-Rivas et al., 2015). Familial isolated pituitary adenoma (FIPA) and pituitary adenoma predisposition (PAP) are terms referring to families in which 2 or more individuals develop pituitary tumors. Within a family, tumor types can be heterogeneous, with members of the same family having GH-secreting, prolactin-secreting, ACTH-secreting, or nonsecreting adenomas; in contrast, some families are homogeneous with regard to tumor type. Familial isolated somatotropinoma refers specifically to GH-secreting tumors and is usually associated with an acromegaly phenotype. Thus, FIS is a subset of FIPA or PAP (Toledo et al., 2007). Schlechte (2003) discussed prolactinoma in general terms as a clinical, diagnostic, and therapeutic problem. Genetic Heterogeneity of Pituitary Adenomas Also see pituitary adenoma-2 (PITA2; 300943), caused by mutation in the GPR101 gene (300393); pituitary adenoma-3 (PITA3; 617686), caused by somatic activating mutations in the GNAS1 gene (139320); pituitary adenoma-4 (PITA4; 219090), caused by somatic mutation in the USP8 gene (603158); and pituitary adenoma-5 (PITA5; 617540), caused by mutation in the CDH23 gene (605516). Patients with the chromosome Xq26.3 microduplication syndrome (300942) have growth hormone-secreting adenomas. Familial acromegaly can also occur in association with multiple endocrine neoplasia type I (MEN1; 131100), Carney complex (CNC1; 160980), and the McCune-Albright syndrome (174800). Rostomyan et al. (2015) performed a retrospective analysis of 208 patients with pituitary gigantism due to pituitary adenoma or hyperplasia. Most patients (78.4%) were male, and the median onset of rapid growth was 13 years of age for boys and 11 years for girls. Of the 143 patients who consented to genetic testing, 29% had AIP mutations, and microduplication at Xq26.3 (XLAG; 300942) was present in 2 familial isolated pituitary adenoma kindreds and in 10 sporadic patients. Rostomyan et al. (2015) noted that no genetic etiology was identified in more than 50% of the cases, and that the genetically unexplained cases showed more aggressive disease in terms of invasion, hormone levels, and lower control rates.  http://www.omim.org/entry/102200