Pituitary adenoma a constitutional duplication of a chromosome Xq26.3 including "GPR101", or mosaicism for the duplication (present in a minority of cells) in the case of isolated male patients. X-LAG causes about 10% of cases of pituitary gigantism. The pituitary gland or hypophysis is often referred to as the "master gland" of the human body. Part of the hypothalamic-pituitary axis, it controls most of the body's endocrine functions via the secretion of various hormones into the circulatory system. The pituitary gland is located below the brain in a depression (fossa) of the sphenoid bone known as the sella turcica. Although anatomically and
Pituitary adenoma interacting protein" ("AIP") gene , and duplications in chromosome Xq26.3 that include the "GPR101" gene that also causes X-linked acrogigantism (X-LAG) syndrome. About 15-20% of FIPA families carry a germline "AIP" gene mutation or deletion, and the disease occurs as autosomal dominant with incomplete penetrance, meaning that about 20% of AIP mutation carriers will develop a pituitary adenoma. "AIP" mutation associated pituitary adenomas (either presenting as FIPA or as individual, non familial cases) are usually growth hormone secreting (acromegaly) or prolactin secreting (prolactinoma) adenomas that are large (macroadenomas) and often occur in children, adolescents and young adults. Daly and colleagues