Patients

This retrospective study was performed at the Clinic for Endocrinology, Diabetes and Metabolic Diseases in Belgrade, Clinical Center of Serbia. Genetic analysis of MEN1 gene was performed at the same institution. In the period from January 2004 until December 2016 MEN1 syndrome was diagnosed in 90 consecutive patients according to following criteria: 1) clinical – two or more major endocrine tumors: parathyroid, pituitary or pNET, 2) familial – one major tumor and a first degree relative with clinical diagnosis of MEN1, 3) genetic – mutation in MEN1 gene, including those with no clinical signs of MEN1 (12). All the patients underwent routine, sitespecific, diagnostic procedures according to current diagnostic guidelines, to confirm the presence of tumors (CT/MRI, Octreoscan/Ga⁶⁸ PET CT, biochemical and hormonal measurements, histopathological analysis after the surgery or biopsy) (13, 14, 15, 16, 17, 18, 19). Genetic analysis MEN1 gene performed in all patients. Data from patients’ medical records were retrospectively studied and analyzed. MEN1 patients were classified as familial cases if two or more members of the pedigree were diagnosed with MEN1 tumors. Patients with no MEN1 tumors or mutation in the family where classified as sporadic, irrespective of patient’s mutational status. Age at onset was defined as the age at which the first tumor occurred. Informed consent was obtained from all patients included in the study. All procedures were carried out in conformance with the Declaration of Helsinki ethical guidelines. The study was approved by the institutional Ethical committee.