Mutations in MEN1 gene and therefore mutant protein menin predispose patients to multiple endocrine neoplasia type 1 (MEN1) syndrome, which is characterized by the occurrence of multiple endocrine tumors, mainly affecting the parathyroid glands, pituitary (anterior lobe) and pancreatic islets [1, 3−3]. The gene discussed is MEN1; the disease is multiple endocrine neoplasia type 1.