Multiple endocrine neoplasia type 4 (MEN4, OMIM #610755) is a genetic disease caused by pathogenic variants in the CDKN1B<\/em> gene. It leads to a predisposition to parathyroid adenomas with primary hyperparathyroidism (PHPT) and tumors of the adenohypophysis (anterior pituitary neuroendocrine tumors, PitNET) and is, therefore, similar to the clinical presentation of MEN1. In addition, renal angiomyolipomas, neuroendocrine tumors of the gastroenteropancreatic tract, and tumors of the uterus, adrenal glands, and thyroid may occur as well.<\/p>\n<\/div> Synonym:<\/p>\n<\/div><\/div><\/div> CDKN1B related MEN<\/p>\n<\/div><\/div><\/div><\/div> Gene:<\/p>\n<\/div><\/div><\/div> CDKN1B<\/i><\/p>\n<\/div><\/div><\/div><\/div> Gene \u00adproduct:<\/p>\n<\/div><\/div><\/div> p27kip1<\/sup><\/p>\n<\/div><\/div><\/div><\/div> Function:<\/p>\n<\/div><\/div><\/div> The cyclin-dependent kinase inhibitor 1B is important in blocking the cell cycle.<\/p>\n<\/div><\/div><\/div><\/div> Pattern of inheritance:<\/p>\n<\/div><\/div><\/div> Autosomal dominant<\/p>\n<\/div><\/div><\/div><\/div> Prevalence:<\/p>\n<\/div><\/div><\/div> Very rare, exact numbers unknown<\/p>\n<\/div><\/div><\/div><\/div> Genotype-phenotype correlation:<\/p>\n<\/div><\/div><\/div> 13 different pathogenic variants have been found to date; a clear genotype-phenotype correlation is not yet known.<\/p>\n<\/div><\/div><\/div><\/div> Penetrance:<\/p>\n<\/div><\/div><\/div> 100% for PHPT<\/p>\n<\/div><\/div><\/div><\/div><\/div><\/div>