Germline mutations cause syndromic pituitary tumors including MEN1 (multiple endocrine neoplasia type 1) (MEN1), MEN4 (cyclin-dependent kinase inhibitor 1B: CDKN1B), Carney complex (type 1 alpha regulatory subunit of protein kinase A: PRKAR1A), McCune–Albright syndrome (GNAS), and familial isolated pituitary adenoma (FIPA) (aryl hydrocarbon receptor-interacting protein: AIP) [1,60]. Here, PRKAR1A is linked to familial isolated pituitary adenoma.