While most cases are sporadic, there are several familial syndromes, such as multiple endocrine neoplasia type 1 (MEN1) and 4 (MEN4), familial isolated pituitary adenoma (FIPA) and Carney complex, as well as the sporadic germline mosaic disorder McCune-Albright disease, that predispose to pituitary hyperplasia and neoplasia, causing acromegaly or gigantism [6,7]. The gene discussed is CDKN1B; the disease is Carney complex.