Familial pituitary adenomas occurr in the classical syndromes of MEN1 and Carney 
Complex as well as in Familial Isolated Pituitary Adenomas (FIPA), an autosomal 
dominant disease with incomplete penetrance. In some families and also rarely in 
sporadic tumours germline mutations of a gene located on chromosome 11q13 known 
as the aryl hydrocarbon receptor interacting protein have been found. This 
article discusses the AIP mutations in these groups and the different molecular 
interactions of AIP that may play a role in pituitary tumour formation.