MEN1 gene mutation analysis in Italian patients with multiple endocrine neoplasia type 1

Multiple endocrine neoplasia type 1 (MEN 1) is a familial syndrome characterized by parathyroid, enteropancreatic and pituitary tumors. The gene responsible for this syndrome is localized at chromosomal 11q13 region and DNA markers from this region cosegregate with the disease. The recent identification of the MEN1 gene, encoding for a protein termed menin of 610 amino acids, allowed mutational screening to be performed both in affected families and sporadic cases. To date many different heterozygous mutations, spreading across all the encoding sequence, have been identified in MEN 1 patients with no apparent mutational hot spots or genotype-phenotype correlation. To analyze the genetic alterations of the MEN1 gene occurring in Italian patients we performed mutational screening by Denaturant Gradient Gel Electrophoresis followed by sequencing of exons 2-10 of the MEN1 gene in 27 Italian MEN 1 families and in five sporadic cases. We identified 17 different heterozygous mutations in 60% of analyzed cases. Twelve of these mutations are novel. Two mutations each occurred twice in unrelated families but no evidence of genotype-phenotype correlation can be established for these families. The extension of genetic diagnosis to asymptomatic family members allowed the identification of 10 MEN1 mutant gene carriers, one newly described and nine previously detected by linkage analysis with DNA markers from the 11q13 region. Our findings add new information to the diversity of mutations occurring in the MEN1 gene and confirm that the mutational screening of MEN 1 is a useful approach to detect individuals at higher risk of developing MEN 1-associated tumors.     

Expression of the MEN-1 gene in a large kindred with multiple endocrine neoplasia type 1

Burgess JR, Greenaway TM, Shepherd JJ (Royal Hobart Hospital, and University of Tasmania, Hobart, Tasmania, Australia). Expression of the MEN-1 gene in a large kindred with multiple endocrine neoplasia type 1 (Minisymposium: MEN & VHL). J Intern Med 1998; 243 : 465–70.
In 1983 a large family with MEN-1 (designated Tasman 1) was identified in Tasmania. Kindred screening and case follow-up over the subsequent 15 years has yielded data on over 160 MEN-1-affected patients. Hyperparathyroidism is present in over 60% of gene carriers by age 20 years and 95% by age 30 years. Hyperplasia is the characteristic pathological finding. Kaplan–Meier analysis indicates hyperparathyroidism recurs in the majority of patients despite near-total parathyroidectomy. Gastrinoma, 'nonfunctioning' pancreatic adenoma and insulinoma occur in up to 60, 50 and 10% of patients, respectively. Metastatic gastroenteropancreatic (GEP) tumours develop in up to 35% of family members, being frequent in some branches of Tasman 1, whilst rare in others. Pituitary disease developed in 19% of patients. Prolactinoma and 'nonfunctioning' adenoma account for 76 and 24%, respectively, of pituitary abnormalities. Prolactinomas exhibit clustering within branches of the Tasman 1 kindred. Adrenal adenomas occur in 36% of patients. The majority of adrenal lesions are benign and nonsecretory and develop in association with pancreatic neoplasia. Carcinoid tumours are uncommon but important malignancies. Malignant thymic carcinoid occurs in male patients, whereas bronchial carcinoid occurs predominantly in women. Prior to recognition of MEN-1 in Tasman 1, complications of hyperparathyroidism and malignancy accounted for the majority of patient mortality. Since commencement of prospective screening, malignant GEP tumours and cardiovascular disease have become the most prevalent causes of death amongst MEN-1-affected patients.     

Thymic carcinoids in multiple endocrine neoplasia type 1

Teh BT (Karolinska Hospital, Stockholm, Sweden). Thymic carcinoids in multiple endocrine neoplasia type 1 (Minisymposium: MEN & VHL). J Intern Med 1998; 243 : 501–4.
Thymic carcinoid is a rare malignancy with about 150 cases reported to date. It is associated with multiple endocrine neoplasia type 1 (MEN-1), but compared with other MEN-1-related neoplasia little is known about it. We have recently described and studied 20 MEN-1-related cases and found that up to 25% of all reported thymic carcinoids are MEN-1 related. It is an insidious tumour not associated with Cushing's syndrome or carcinoid syndrome. Local invasion, recurrence and distant metastasis are common with no known effective treatment. Its male predominance, the absence of loss of heterozygosity (LOH) in the MEN1 region, clustering in some MEN-1 families and the findings of different MEN1 mutations in these clustered families suggest the involvement of additional aetiological factors. We propose that computed tomography (CT) or magnetic resonance imaging (MRI) of the chest should be included as part of the clinical workup for all MEN-1 patients. Prophylactic thymectomy should be considered during subtotal or total parathyroidectomy on MEN-1 patients to reduce the risk of this malignancy.     

Cushing's syndrome in multiple endocrine neoplasia type 1

Objective In patients with multiple endocrine neoplasia type 1 (MEN1), Cushing’s syndrome (CS) from endogenous hypercortisolism can result from pituitary, adrenal or other endocrine tumours. The purpose of this study was to characterize the range of presentations of CS in a large series of MEN1 patients. Design Retrospective review of NIH Clinical Center inpatient records over an approximately 40‐year period. Patients Nineteen patients (eight males, 11 females) with CS and MEN1. Measurements Biochemical, imaging, surgical and pathological findings. Results An aetiology was determined for 14 of the 19 patients with CS and MEN1: 11 (79%) had Cushing’s disease (CD) and three (21%) had ACTH‐independent CS owing to adrenal tumours, frequencies indistinguishable from sporadic CS. Three of 11 MEN1 patients with CD (27%) had additional non‐ACTH‐secreting pituitary microadenomas identified at surgery, an incidence 10‐fold higher than in sporadic CD. Ninety‐one per cent of MEN1 patients with CD were cured after surgery. Two of three MEN1 patients with ACTH‐independent CS (67%) had adrenocortical carcinoma. One patient with adrenal cancer and another with adrenal adenoma were cured by unilateral adrenalectomy. No case of ectopic ACTH secretion was identified in our patient cohort. The aetiology of CS could not be defined in five patients; in three of these, hypercortisolism appeared to resolve spontaneously. Conclusions The tumour multiplicity of MEN1 can be reflected in the anterior pituitary, MEN1‐associated ACTH‐independent CS may be associated with aggressive adrenocortical disease and an aetiology for CS in MEN1 may be elusive in a substantial minority of patients.     

一个多发性内分泌腺瘤病2A型家系的RET原癌基因突变检测

目的 检测一个多发性内分泌腺瘤病(MEN)2A型家系中RET原癌基因的突变情况.方法 观察一个MEN2A家系成员的表型,并对与MEN相关的且点突变率较高的RET原癌基因第10和11外显子进行PCR产物直接DNA测序以了解其杂合性.结果 家系中4名家族成员均存在RET原癌基因第11外显子Cys(TGC)634Arg(CGC)错义突变和Gly(GGT)691Ser(AGT)的单核苷酸多态性,另有1名成员仅存在RET原癌基因Gly(GGT)691Set(AGT)的单核苷酸多态性.经B超检查发现其中2名成员双侧甲状腺及一侧肾上腺和一侧甲状旁腺有实性占位病变,1名成员双侧甲状腺及一侧肾上腺有实性占位病变,1名成员双侧甲状腺、双侧肾上腺和一侧甲状旁腺有实性占位病变,1名成员仅有甲状腺多发性小结节.另外有3名成员B超检查有异常,但无基因突变.结论 对MEN2A家系的基因分析证实RET原癌基因第11外显子634位密码子存在突变和(或)691位密码子存在单核苷酸多态性,对MEN2A能在基因水平作出诊断.     

Experience with multiple endocrine neoplasia type 1 screening

Abstract. Screening for multiple endocrine neoplasia type 1 (MEN1) may be conducted for a variety of reasons. The principal aims may be more or less scientific, such as early identification of the trait. Other reasons for screening comprise attempts to avoid endocrine morbidity and possibly forthcoming problems from malignant transformation, as well as attempts to identify and treat gene carriers with a clinically overt disease. Several reports have substantiated the diagnostic yield from screening efforts among MEN1 kindreds. Such increases in detection of the disease ideally should be accompanied by enhanced rates of survival in order to fully justify an unlimited search for the trait. However, studies are lacking a clearly verifying reduction of mortality from the detection of presymptomatic MEN1 individuals. While waiting for the results of survival studies in progress, the generally prevailing opinion favours widespread screening because of the evidently decreased morbidity resulting from early diagnosis of the MEN1 trait, which apparently persists even during decades of follow-up. This paper presents the clinical features of the disease and experience derived from a prospective screening programme for MEN1 detection.     

Candidate genes for multiple endocrine neoplasia type 1

Abstract. The aim of this study was to isolate and characterize candidates for the multiple endocrine neoplasia type 1 (MEN1) gene. The development of tumours related to MEN1 is associated with somatic deletions involving the MEN1 locus, suggesting inactivation of a tumour-suppressor gene in this region. We have isolated five cDNA candidates located within the 900 kb remaining for the MEN1 gene, determined their sequence, and characterized their expression in normal tissues and several endocrine tumours. One of the candidates, encoding for phospholipase C-β3, showed properties consistent with the idea of a tumour-suppressor gene.     

Pheochromocytoma in multiple endocrine neoplasia type 2: a prospective study

OBJECTIVE: The aim of this prospective study is to update our knowledge of the chronology of pheochromocytoma occurrence in multiple endocrine neoplasia type 2 (MEN 2), and to better manage MEN 2 patients after the genetic diagnosis. DESIGN: Eighty-seven non-index gene carrier MEN 2 patients were included in this prospective study: 84 patients with MEN 2A (from 52 families) and 3 with MEN 2B (from 3 families). METHODS: Medullary thyroid carcinoma (MTC) was diagnosed by measuring plasma calcitonin in basal conditions or after pentagastrin stimulation. The search for pheochromocytoma consisted of clinical evaluation, 24 h determination of urinary catecholamines and adrenal imaging. The mean age at genetic diagnosis of MEN 2 was 14.0+/-7.0 years, the mean duration for the follow-up was 7.6+/-2.8 years. RESULTS: All 87 patients had a MTC detected at the same time as the genetic diagnosis was made. Urinary catecholamine measurements led to the diagnosis of pheochromocytoma and a combination of imaging techniques enabled the correct localization of both unilateral or bilateral adrenal involvement. Pheochromocytoma was detected simultaneously with MTC in only seven patients, and seven others were detected throughout the follow-up. Of the 14 patients with pheochromocytoma, 11 had bilateral involvement: nine were initially bilateral and two became so during follow-up. CONCLUSION: This study demonstrates that in MEN 2, MTC is the lesion which appears earliest. Pheochromocytoma develops later during the evolution of the disease, and necessitates regular clinical and biological monitoring throughout follow-up. Determination of urinary and/or plasma catecholamines and metanephrines should be performed to detect pheochromocytoma. Imaging techniques lead to the detection of both unilateral and bilateral pheochromocytoma, thus making video-assisted laparoscopic adrenalectomy possible.     

Primary hyperparathyroidism in multiple endocrine neoplasia type 2A

Abstract. The rarity of primary hyperparathyroidism (PHPT) in multiple endocrine neoplasia type 2A (MEN 2A) led us to study clinical findings, surgical therapy and outcome in 67 patients in order to evaluate our therapeutic strategy. The retrospective study was based on cases registered by the EUROMEN study group (nine participating centres) from 1972 to 1993. Characteristics of PHPT in 67 patients (41 females, 26 males) with MEN 2A were reviewed. All patients underwent exploratory neck surgery; PHPT was confirmed histologically and/or biochemically. The median age at diagnosis of PHPT was 38 years. In 75% of the patients, PHPT and medullary thyroid carcinoma were diagnosed synchronously, while in 4%, PHPT was diagnosed earlier. In 18% of the patients, PHPT was diagnosed after thyroidectomy, and in 3%, after discovery of pheochromocytoma. Primary hyperparathyroidism was asymptomatic in 84% of the patients; 15% suffered from renal stones. Serum calcium was slightly elevated in 69% (2.9 ± 0.2 mmol^-1) and normal in 16% of subjects. A single adenomectomy was performed in 42% of the patients, subtotal parathyroidectomy in 31% and total parathyroidectomy with autotransplantation in 16%. Independent from the extent of resection, cure was achieved in 94% of the patients, including 13% with hypoparathyroidism; hypercalcaemia persisted in 3% and no information was available in 3%. In an 8-year follow-up, hypercalcaemia recurred in 12% of the patients, although half had undergone parathyroidectomy totally or subtotally. Conclusion . MEN 2A-related PHPT is characterized by a mild hypercalcemia which is mostly asymptomatic and can be cured by simple resection of an enlarged parathyroid gland in most cases.     

Mediastinal seminoma in a patient with multiple endocrine neoplasia type 1

A patient with multiple endocrine neoplasia type 1 (MEN1) developed a mediastinal seminoma. The patient was a 46-year-old man who presented with respiratory symptoms. A diagnosis of mediastinal seminoma was pathologically confirmed and a complete remission was achieved by chemotherapy. During his hospital stay, hyperparathyroidism and multiple pancreatic tumors associated with hypergastrinemia were found. A diagnosis of MEN1 was made genetically. Although patients with MEN1 manifest a variety of neoplastic disorders, no cases of concurrent seminoma and MEN1 have previously been reported. In addition, no etiological relationship between seminoma and MEN1 has yet been reported.     

A novel deletion of the MEN1 gene in a large family of multiple endocrine neoplasia type 1 (MEN1) with aggressive phenotype

Context The MEN1 syndrome is associated with parathyroid, pancreatic and pituitary tumours and is caused by mutations in the MEN1 gene. In general, there is no genotype–phenotype correlation. Objectives To characterize a large family with MEN1 with aggressive tumour behaviour: malignant pancreatic endocrine tumours were present in five affected subjects and were the presenting features in three subjects. Design The coding region of MEN1 was sequenced. Gene copy number analysis was performed by multiplex ligation‐dependent probe amplification (MLPA) and array comparative genomic hybridization (aCGH). Loss of heterozygosity (LOH) in tumour tissue was studied by microsatellite analysis. Insulin‐like growth factor II (IGF‐II) and CDKN1C/p57KIP2 expression were investigated by immunohistochemistry. Results Mutation screening by conventional PCR sequence analysis of patients’ peripheral blood DNA did not reveal any mutation in the MEN1 or CDKN1B gene. Gene copy number analysis by MLPA and aCGH demonstrated a novel monoallelic deletion of 5 kb genomic DNA involving the MEN1 promoter and exons 1 and 2. LOH analysis indicated somatic deletion of maternal chromosome 11, including MEN1 locus (11q13) and 11p15 imprinting control regions (ICR). Methylation analysis of ICR demonstrated ICR1 hypermethylation and ICR2 hypomethylation in the tumour specimens. ICR1 and ICR2 control the expression of IGF‐2 and CDKN1C/p57KIP2, respectively. Immunohistochemistry showed that expression of paternally expressed IGF‐2 was up‐regulated and the maternally expressed CDKN1C/p57KIP2 was lost in the pancreatic endocrine tumours. Conclusions Gene copy number analysis by MLPA should be considered in patients with negative conventional mutation screening. Although large MEN1 deletion causes MEN1, disruption of imprinted CDKN1C/p57KIP2 and IGF‐2 gene expression may contribute to tumour progression and aggressive phenotype.     

Novel 1113delC menin gene mutation in a Polish family with multiple endocrine neoplasia type 1 syndrome

We report the case of a 32-year-old male with hypercalcemia and recurrent nephrolithiasis as a symptom of primary hyperparathyroidism, hypoglycemia due to insulinoma, microprolactinoma, and a large, partially calcified tumor of the upper right leg. The patient underwent several surgical interventions including subtotal parathyreoidectomy, partial pancreatectomy, and percutaneous nephrolithotrypsy. Regular treatment with bromocriptine was required for normalization of serum prolactin concentration. His only sibling, a 26-year-old sister, suffered from microprolactinoma and had been treated with bromocriptine for 6 years. Their father had suffered from recurrent kidney stones and peptic ulcer and died at the age of 34. A novel 1113delC mutation within exon 7 of the menin gene was found in both siblings. This mutation results in a frame-shift with missense translation of the subsequent residual acids and preterm termination of the peptide at codon 357.     

Acromegaly in a multiple endocrine neoplasia type 1 (MEN1) family with low penetrance of the disease

Multiple endocrine neoplasia type 1 (MEN1) is an inherited syndrome that is characterised by the occurrence of tumours in the parathyroid glands, the endocrine pancreas, the pituitary gland and the adrenal glands and by neuroendocrine carcinoid tumours, often at a young age. The penetrance of MEN1 among gene carriers is reported to be high; 82-99% at age 50. We present a patient with a history of parathyroid adenomas also showing signs of acromegaly. He turned out to be a carrier of a MEN1 germ-line mutation in intron 3 (IVS3-6C > G). This germ-line mutation was also found in nine of his family members. However, none of these relatives have developed any MEN1-related lesion yet, although several are older than 60 years. To our knowledge, a MEN1 family with as few clinical features as this family has not been reported to date. Because MEN1 patients have an increased risk of developing acromegaly, insulin-like growth factor (IGF-I) levels are monitored periodically. We investigated whether IGF-I levels might serve as a presymptomatic marker for acromegaly; 9% (3/33) of MEN1 patients showed temporary IGF-I elevations. One patient (1/3) later developed clinical signs of acromegaly. Possibly, acromegaly in MEN1 is preceded by a transient preacromegalic state.     

Colonic manifestations of multiple endocrine neoplasia type 2B

Multiple endocrine neoplasia type 2B is best known for its endocrine manifestations and typical phenotype. The gastrointestinal manifestations, however, are also an important and commonly unrecognized component of the syndrome. We present four cases that demonstrate the varied presentation of patients with colonic manifestations of multiple endocrine neoplasia type 2B. We discuss the cause, diagnostic significance, and management of the colonic disease that is a component of multiple endocrine neoplasia type 2B.