Hypothalamic–pituitary–gonadal axis Hypothalamic–pituitary–gonadal axis The hypothalamic–pituitary–gonadal axis (HPG axis) refers to the hypothalamus, pituitary gland, and gonadal glands as if these individual endocrine glands were a single entity. Because these glands often act in concert, physiologists and endocrinologists find it convenient and descriptive to speak of them as a single system. The HPG axis plays a critical part in the development and regulation of a number of the body's systems, such as the reproductive and immune systems. Fluctuations in this axis cause changes in the hormones produced by each gland and have various local and systemic effects on the body. The axis
Pituitary adenoma showed that acromegaly cases with "AIP" mutations occurred about 20 years before acromegaly cases without "AIP" mutations and these tumors are large and relatively treatment resistant. Due to their young age at onset, "AIP" mutations are the most frequent genetic cause of pituitary gigantism (29% of cases). X-LAG is a rare syndrome of very early childhood onset pituitary tumors/hyperplasia that leads to growth hormone excess and severe overgrowth and pituitary gigantism. Three FIPA families with X-LAG have been reported to date all of which had transmission of a chromosome Xq26.3 duplication from affected mother to affected son . The disease