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In 1953, for the first time, Paul Wermer described a family presenting endocrine gland neoplasms over several generations. The transmission was autosomal dominant and the penetrance was high. Forty years later in 1997, the multiple endocrine neoplasia type 1 (MEN1) gene was sequenced, thus enabling diagnosis and early optimal treatment. Patients carrying the MEN1 gene present endocrine but also non-endocrine tumors. Parathyroid, pancreatic and pituitary impairment are the three main types of endocrine involvement. The present article details therapeutic management of hyperparathyroidism, neuroendocrine pancreatic tumors and pituitary adenomas in patients carrying the MEN1 gene. Significant therapeutic progress has in fact been made in the last few years. As concerns the parathyroid glands, screening of family members and regular monitoring of affected subjects now raise the question of early management of parathyroid lesions and optimal timing of parathyroid surgery. As concerns the duodenum-pancreas, proton-pump inhibitors are able to control gastrin-secreting syndrome, reducing mortality in MEN1 patients. Mortality in MEN1 patients is no longer mainly secondary to uncontrolled hormonal secretion but to metastatic (mainly pancreatic) disease progression. Tumor risk requires regular monitoring of morphological assessment, leading to iterative pancreatic surgery in a large number of patients. Finally, pituitary adenomas in MEN1 patients are traditionally described as aggressive, invasive and resistant to medical treatment. However, regular pituitary screening showed them to be in fact infra-centimetric and non-secreting in the majority of patients. Consequently, it is necessary to regularly monitor MEN1 patients, with regular clinical, biological and morphological work-up. Several studies showed that this regular monitoring impairs quality of life. Building a relationship of trust between patients and care provider is therefore essential. It enables the patient to be referred for psychological or psychiatric care in difficult times, providing long-term support and preventing any breakdown in continuity of care., (Copyright © 2021 Elsevier Masson SAS. All rights reserved.)

Multiple Endocrine Neoplasia Type 1 (NEM1) is related to mutations of the menin gene. It is an autosomal dominant disease. Its prevalence is about 1/30 000 with a hugh penetrance. There is no genotype-phenotype correlation. This hereditary syndrome is characterized by the presence of tumors of the endocrine system (parathyroid, endocrine pancreas, pituitary and adrenal gland). Other disorders have also been described (bronchial and thymic carcinoid tumor, breast cancer, skin lesions). Management must take into account the specificities of these pathologies in NEM1 compared to sporadic forms (young age at diagnosis, multiple lesions within the same gland, multi-focal disease). © 2019 Published by Elsevier Masson SAS. All rights reserved. Cet article fait partie du numéro supplément Les Must de l'Endocrinologie 2019 réalisé avec le soutien institutionnel de Ipsen-Pharma., (© 2019 Elsevier Masson SAS. Tous droits réservés.)

Context: Multiple Endocrine Neoplasia Type 1 (MEN1) is an autosomal dominant inherited syndrome, related to mutations in the MEN1 gene. Controversial data suggest that the nonsynonymous p.Ala541Thr variant, usually considered as a non-pathogenic polymorphism, may be associated with an increased risk of MEN1-related lesions in carriers., Objective: The aim of this study was to evaluate the pathogenic influence of the p.Ala541Thr variant on clinical and functional outcomes., Patients and Methods: We analysed a series of 55 index patients carrying the p.Ala541Thr variant. Their clinical profile was compared to that of 117 MEN1 patients. The biological impact of the p.Ala541Thr variant on cell growth was additionally investigated on menin-deficient Leydig cell tumour (LCT)10 cells generated from Men1+/Men1- heterozygous knock-out mice, and compared with wild type (WT)., Results: The mean age at first appearance of endocrine lesions was similar in both p.Ala541Thr carriers and MEN1 patients, but no p.Ala541Thr patient had more than one cardinal MEN1 lesion at initial diagnosis. A second MEN1 lesion was diagnosed in 13% of MEN1 patients and in 7% of p.Ala541Thr carriers in the year following preliminary diagnosis. Functional studies on LCT10 cells showed that overexpression of the p.Ala541Thr variant did not inhibit cell growth, which is in direct contrast to results obtained from investigation of WT menin protein., Conclusion: Taken together, these data raise the question of a potential pathogenicity of the p.Ala541Thr missense variant of menin that commonly occurs within the general population. Additional studies are required to investigate whether it may be involved in a low-penetrance MEN1 phenotype., (Copyright © 2014 Elsevier Masson SAS. All rights reserved.)

MEN1 gene mutations predispose carriers to pituitary tumors. Molecular pathways involved in the development of these tumors seem different to what is known in sporadic tumors. Clinical studies showed that all types of adenomas can be found with a predominance of prolactinoma and macroadenoma compared to a control population. These MEN1 tumors seem more aggressive, invasive and resistant to treatment requiring a very careful long-life follow-up. Occurrence of these tumors can be described in the pediatric population and it can be the first and only manifestation of MEN1 for some years asking the question of the systematic screening for MEN1 gene mutation in pediatric population with pituitary adenoma., (Copyright © 2012. Published by Elsevier Masson SAS.)

Pituitary adenomas are benign intracranial neoplasms that present a major clinical concern because of hormonal overproduction or compression symptoms of adjacent structures. Most arise in a sporadic setting with a small percentage developing as a part of familial syndromes such as multiple endocrine neoplasia type 1 (MEN1), Carney complex (CNC), and the recently described familial isolated pituitary adenomas (FIPA) and MEN-4. While the genetic alterations responsible for the formation of sporadic adenomas remain largely unknown, considerable advances have been made in defining culprit genes in these familial syndromes. Mutations in MEN1 and PRKAR1A genes are found in the majority of MEN1 and CNC patients, respectively. About 15% of FIPA kindreds present with mutations of the aryl hydrocarbon receptor-interacting protein (AIP) gene. Mutations in the CDKN1B gene, encoding p27(Kip)¹ were identified in MEN4 cases. Familial tumours appear to differ from their sporadic counterparts not only in genetic basis but also in clinical characteristics. Evidence suggests that, especially in MEN1 and FIPA, they are more aggressive and affect patients at younger age, therefore justifying the importance of early diagnosis. In this review, we summarize the genetic and clinical characteristics of these familial pituitary adenomas., (Copyright © 2010. Published by Elsevier Masson SAS.)

Pituitary adenomas can occur in a familial context, or they can be isolated cases, sometimes due to a predisposing syndrome. In multiple endocrine neoplasia type 1, they often associate with a mutation of the menin gene, a tumor-suppressing gene. A new germinal mutation predisposing to the development of multiple endocrine neoplasias has recently been identified in MENI-negative subjects on the gene CDKN1B encoding for p27(kip1)protein. Carney Complex syndrome--a rare disease--is in more than 60% of the cases linked to the inactivation mutation of a gene located on 17q22-24 that encodes the regulatory subunit 1 of protein kinase A, PRKARIA. Isolated familial pituitary adenomas represent 1.9 to 3.2% of the population of subjects presenting a pituitary adenoma. Low penetrance non-sense mutations, Q14X, IVS3-IG>A and R304X, in 11q12-11q13 region encoding AIP protein, (Aryl hydrocarbon receptor Interacting Protein), have been described by Vierimaa et al, in Finish patients with pituitary adenoma predispositions.

Wermer's syndrome or Multiple Endocrine Neoplasia Type-1 (MEN1) is an autosomal dominant inherited disease, related to mutations in MEN1, an approximately 10-kb gene encoding menin, localized on chromosome 11q13. The Endocrine Tumor Group (GTE) has set up a MEN1 observatory of 1001 regularly followed MEN1 cases. This observatory aims at registering and evaluating MEN1 cases in a large cohort. Any new study on a particular unexplored aspect of the disease may be proposed by a physician to the GTE. This article describes the way to diagnose a new MEN1 case and to register it. Procedures for participating in a new study are presented. Some original results are quoted.

Multiple Endocrine Neoplasia type 1 (MEN1) is an autosomal dominant hereditary syndrome (OMIM 131100) due to MEN1 gene mutations, predisposing to the development of hyperplasic and tumoral lesions of neuroendocrine tissues. Since the identification of the gene in 1997, more than 400 different mutations of MEN1 have been registered. Genotypic analysis of MEN1 remains fastidious and must be reserved to targeted situations. If the lesions appear in a familial assessed context, there is a strong argument to search for MEN1 mutation. This is not the case in a sporadic context. With experience acquired in our laboratory, we evaluated the frequency of MEN1 mutations in patients with sporadic presentations. Our aim was to better define criteria for MEN1 genotypic analysis. One hundred and twenty four blood samples from unrelated patients, who gave their written informed consent, were analyzed. These patients exhibited 1 to 4 manifestations of MEN1 without any familial context. After DNA extraction, the analysis was undertaken by PCR-sequencing of all the MEN1 coding exons and exon/intron boundaries or by PCR of the pre-screened fragments alone, a technique made possible by indirect screening mutation methods. Mutations were identified by comparing the sequences to the reference MEN1 sequence available from GENBANK (U93237.1). Mutations were identified in 19 patients, with variable prevalence according to clinical manifestations: 100% for patients with 4 manifestations, 45.5% for patients with 3 manifestations, 19% for patients with 2 manifestations and 2% for patients with only one manifestation. Mutations were: 11 point variations (58%), including 2 splicing sites and 8 frameshift mutations (42%) including 5 deletions, 2 insertions and 1 insertion/deletion; one mutation was identified twice. We showed a relationship between clinical presentation and MEN1 mutation identification, especially with the number of clinical manifestations but also with the type of manifestation. Pancreatic manifestations were significantly linked with probability of mutation. In a sporadic context with at least two established manifestations of MEN1, the overall probability of identifying a mutation was 26%, warranting MEN1 genotypic analysis.

Multiple endocrine neoplasia (MEN) types 1 and 2 syndromes are rare hereditary cancer syndromes expressing a variety of endocrine and non-endocrine neoplasias and lesions. The improving of both molecular and clinical genetics knowledge helps health care providers in the whole spectrum of the clinical managements of MEN patients. The MEN1 gene, a tumour suppressor gene, is responsible of MEN1 syndrome, and is probably involved in the regulation of several cell functions, including DNA replication and repair and transcriptional machinery. RET proto-oncogene encodes for a receptor tyrosine kinase protein whose expression is fundamental for appropriate migration, development and differentiation of neuroendocrine cells originating from neural crest. Currently, DNA testing makes possible the early identification of germline mutation in asymptomatic mutant gene carriers in both MEN syndromes. Consequently, the combination of new genetic and diagnostic tools could permit a precocious detection of MEN-associated neoplasms, and in particular the identification of a strong genotype-phenotype correlations in MEN2 syndrome demonstrates an improving outcome and quality of life for affected subjects.

Multiple Endocrine Neoplasia type 1 (MEN 1) is an autosomal dominant syndrome characterized by neoplasia of the parathyroid glands, the endocrine pancreas and the anterior pituitary gland. Recently the identification on chromosome 11 (locus q13) of the gene responsible for MEN 1 has allowed direct genetic diagnosis of MEN 1-affected family members. To date almost 300 families have been described and genetically characterized. The genetic etiology of most pituitary tumours remains unknown. Pituitary adenomas can develop sporadically or as a part of multiple endocrine neoplasia type 1. In this review, the recently published data on the pathology of the MEN 1 syndrome will be summarized. The clinical, morphological and genetic aspects of sporadic and MEN 1-associated pituitary adenomas will be outlined.

Multiple Endocrine Neoplasia type 1 (MEN1, OMIM 131100, Wermer syndrome) is characterized by inherited predisposition to primary hyperparathyroidism, endocrine pancreatic-duodenal, pituitary, adrenal glands tumors and benign and/or malignant proliferations of diffuse neuroendocrine tumors in thymus and bronchi, formerly defined as carcinoid tumors. Minor lesions have been observed in MEN1 patients such as cutaneous tumors (angiofibroma, lipoma, lentiginosis), thyroid epithelioma and tumors of the central nervous system, mainly spinal ependymoma. The MEN1 gene, a locus encompassing a 9 kb of genomic sequence contains 10 exons, the first exon being untranslated. The protein encoded by this gene was called menin and has been shown to contain two nuclear localization signals (NLS), suggesting a major function in the nucleus. Germline MEN1 mutations have been described in more than 150 families and are spread throughout the entire coding sequence. More than 70% of the mutations alter one or both NLS and no genotype-phenotype correlations were found to date. The MEN1 gene seems to be involved in a 20-30% of sporadic parathyroid and pancreatic/bronchic neuroendocrine tumors, but less than 1% of pituitary sporadic tumors. Further knowledge on the intracellular function of menin will be needed to understand the pathogenic effect of truncating and missense mutations of this gene in the initiation of endocrine cells tumorigenesis.

Genetic studies of neuroendocrine tumors were mainly performed on the basis of major syndromes predisposing to endocrine and associated proliferative lesions. Carcinoid tumors and tumors of the pancreatic islet cells occur in Multiple Endocrine Neoplasia type 1, Neurofibromatosis type I, Von Hippel-Lindau disease, Tuberous Sclerosis, suggesting that alterations of the major genes responsible for these genetic syndromes are crucial mechanisms in the neuroendocrine pathogenesis. Tumoral progression and metastasis result from secondary genetic events or deregulation involving specific genes, oncogenes, suppressor genes, and growth factors. Mechanisms involving mitosis, cell cycle, and cellular adhesion might be relevant in the metastatic process. This report is an overview of experimental data on this topic and attempt to understand the major events inducing a malignant evolution of the normal neuroendocrine tissue.

Multiple Endocrine Neoplasia type 1 (MEN 1) is an autosomal dominant familial syndrome characterized by involvement of several endocrine glands, including parathyroid, pancreatic islet cells, anterior pituitary and diffuse neuroendocrine tissues (carcinoids). The gene causing this syndrome has been localized to chromosome 11 but was not cloned up-to-date. Pre-clinical diagnosis in predisposed MEN 1 families was based on the use of genetic linkage analysis with polymorphic DNA probes flanking the disease locus. The set-up collaborative multi-disciplinar medical and surgical network facilitates further clinical and genetic studies on MEN 1 families. Semiological course of the disease is complex and the main objective in clinical follow-up of patients and related is to limit the probability of misdiagnosis. The present report describe the clinical and genetic analysis in a MEN 1 family and the difficulties related to diagnose the disease. An interesting observation on two cases of hyperprolactinemia by two individuals further excluded by genetic analysis assess the potential risk of bias in genetic linkage studies in non-well documented families. Concerted analysis of genetic and bio-clinical data permitted the evaluation of each patient and to exclude the risk of MEN 1 in all children tested. This example demonstrates the need of a complete clinical information previously to genetic analysis and a multi-disciplinar and collaborative approach in follow-up of patients in each family.