Endocrine Abstracts

There are a number of established and recently identified inherited or congenital forms of growth hormone (GH) secreting pituitary tumors. These may be caused by an abnormality in the genetic sequence of responsible genes including MEN1, AIP, CDKN1B, and PRKAR1A. Copy number variation for these and other genes may also contribute to pituitary tumorigenesis, such as duplication of the gene GPR101 in X-linked acrogigantism (X-LAG) syndrome. Mosaicism for mutations or copy number variations an also play a causative role in the pathogenesis of pituitary adenomas, including those causing acromegaly and gigantism. Genetic forms of GH secreting pituitary adenomas tend to have more aggressive features than those without a known genetic cause, including a younger age of onset and resistance to medical therapy. Familial isolated pituitary adenomas (FIPA) and MEN1 represent the most frequent causes of genetically related or inherited pituitary adenomas; however to date a genetic component has only been discovered in about 5% of pituitary adenomas overall. In the absence of testing guidelines for all of the various isolated and syndromic forms of pituitary adenomas, clinical characteristics of the patient or kindred are important for guiding the choice of genetic testing.