CDKN1B and multiple endocrine neoplasia type 4: In contrast, syndromic forms (about 5% of all pituitary tumors) include acromegaly as part of a syndromic disease accompanied by other symptoms, often tumors of other endocrine organs, such as multiple endocrine neoplasia type 1 (MEN1), multiple endocrine neoplasia type 4 (MEN4), Carney complex, McCune–Albright syndrome, phaeochromocytoma/paraganglioma (PPGL)-pituitary adenoma association (3PA), Neurofibromatosis type 1, X-linked acrogigantism (X-LAG), or Tuberous Sclerosis Complex (TSC) [88].