Familial isolated pituitary adenoma (FIPA) is characterized by the presence of pituitary adenomas in two or more members of the same family in the absence of other syndromic clinical features, such as those characteristic of multiple endocrine neoplasia (MEN) type 1 and MEN4, Carney complex or tumors related to mutations in the succinate dehydrogenase genes. Here, CDKN1B is linked to pituitary gland adenoma.