A family of MEN1 with a novel germline missense mutation and benign polymorphisms

Phenotypes Associated With MEN1 Syndrome: A Focus on Genotype-Phenotype Correlations

Multiple endocrine neoplasia type 1 (MEN1) is a rare autosomal dominant inherited tumor syndrome, associated with parathyroid, pituitary, and gastro-entero-pancreatic (GEP) neuroendocrine tumors (NETs). MEN1 is usually consequent to different germline and somatic mutations of the MEN1 tumor suppressor gene, although phenocopies have also been reported. This review analyzed main biomedical databases searching for reports on MEN1 gene mutations and focused on aggressive and aberrant clinical manifestations to investigate the potential genotype-phenotype correlation. Despite efforts made by several groups, this link remains elusive to date and evidence that aggressive or aberrant clinical phenotypes may be related to specific mutations has been provided by case reports and small groups of MEN1 patients or families. In such context, a higher risk of aggressive tumor phenotypes has been described in relation to frameshift and non-sense mutations, and predominantly associated with aggressive GEP NETs, particularly pancreatic NETs. In our experience a novel heterozygous missense mutation at c.836C>A in exon 6 was noticed in a MEN1 patient operated for macro-prolactinoma, who progressively developed recurrent parathyroid adenomas, expanding gastrinomas and, long after the first MEN1 manifestation, a neuroendocrine uterine carcinoma. In conclusion, proof of genotype-phenotype correlation is limited but current evidence hints at the need for long-term interdisciplinary surveillance in patients with aggressive phenotypes and genetically confirmed MEN1.

Causes of death and prognostic factors in multiple endocrine neoplasia type 1: a prospective study: comparison of 106 MEN1/Zollinger-Ellison syndrome patients with 1613 literature MEN1 patients with or without pancreatic endocrine tumors

Multiple endocrine neoplasia type 1 (MEN1) is classically characterized by the development of functional or nonfunctional hyperplasia or tumors in endocrine tissues (parathyroid, pancreas, pituitary, adrenal). Because effective treatments have been developed for the hormone excess state, which was a major cause of death in these patients in the past, coupled with the recognition that nonendocrine tumors increasingly develop late in the disease course, the natural history of the disease has changed. An understanding of the current causes of death is important to tailor treatment for these patients and to help identify prognostic factors; however, it is generally lacking.To add to our understanding, we conducted a detailed analysis of the causes of death and prognostic factors from a prospective long-term National Institutes of Health (NIH) study of 106 MEN1 patients with pancreatic endocrine tumors with Zollinger-Ellison syndrome (MEN1/ZES patients) and compared our results to those from the pooled literature data of 227 patients with MEN1 with pancreatic endocrine tumors (MEN1/PET patients) reported in case reports or small series, and to 1386 patients reported in large MEN1 literature series. In the NIH series over a mean follow-up of 24.5 years, 24 (23%) patients died (14 MEN1-related and 10 non-MEN1-related deaths). Comparing the causes of death with the results from the 227 patients in the pooled literature series, we found that no patients died of acute complications due to acid hypersecretion, and 8%-14% died of other hormone excess causes, which is similar to the results in 10 large MEN1 literature series published since 1995. In the 2 series (the NIH and pooled literature series), two-thirds of patients died from an MEN1-related cause and one-third from a non-MEN1-related cause, which agrees with the mean values reported in 10 large MEN1 series in the literature, although in the literature the causes of death varied widely. In the NIH and pooled literature series, the main causes of MEN1-related deaths were due to the malignant nature of the PETs, followed by the malignant nature of thymic carcinoid tumors. These results differ from the results of a number of the literature series, especially those reported before the 1990s. The causes of non-MEN1-related death for the 2 series, in decreasing frequency, were cardiovascular disease, other nonendocrine tumors > lung diseases, cerebrovascular diseases. The most frequent non-MEN1-related tumor deaths were colorectal, renal > lung > breast, oropharyngeal. Although both overall and disease-related survival are better than in the past (30-yr survival of NIH series: 82% overall, 88% disease-related), the mean age at death was 55 years, which is younger than expected for the general population.Detailed analysis of causes of death correlated with clinical, laboratory, and tumor characteristics of patients in the 2 series allowed identification of a number of prognostic factors. Poor prognostic factors included higher fasting gastrin levels, presence of other functional hormonal syndromes, need for >3 parathyroidectomies, presence of liver metastases or distant metastases, aggressive PET growth, large PETs, or the development of new lesions.The results of this study have helped define the causes of death of MEN1 patients at present, and have enabled us to identify a number of prognostic factors that should be helpful in tailoring treatment for these patients for both short- and long-term management, as well as in directing research efforts to better define the natural history of the disease and the most important factors determining long-term survival at present.

Variable clinical expression in patients with a germline MEN1 disease gene mutation: clues to a genotype-phenotype correlation

Multiple endocrine neoplasia type 1 is an inherited endocrine tumor syndrome, predominantly characterized by tumors of the parathyroid glands, gastroenteropancreatic tumors, pituitary adenomas, adrenal adenomas, and neuroendocrine tumors of the thymus, lungs or stomach. Multiple endocrine neoplasia type 1 is caused by germline mutations of the multiple endocrine neoplasia type 1 tumor suppressor gene. The initial germline mutation, loss of the wild-type allele, and modifying genetic and possibly epigenetic and environmental events eventually result in multiple endocrine neoplasia type 1 tumors. Our understanding of the function of the multiple endocrine neoplasia type 1 gene product, menin, has increased significantly over the years. However, to date, no clear genotype-phenotype correlation has been established. In this review we discuss reports on exceptional clinical presentations of multiple endocrine neoplasia type 1, which may provide more insight into the pathogenesis of this disorder and offer clues for a possible genotype-phenotype correlation.

Thymic carcinoid in multiple endocrine neoplasia 1: genotype-phenotype correlation and prevention

Thymic carcinoid is a rare multiple endocrine neoplasia type 1 (MEN1)-associated tumour that is a major cause of death in MEN1 patients. Here, we describe a previously unreported MEN1 family in which two siblings presented with malignant thymic carcinoids. All six siblings share a novel nonsense mutation Q395X on exon 8 of the MEN1 gene. The index patient developed a thymic carcinoid despite an earlier prophylactic transcervical thymectomy, and one other sibling had an incidental malignant thymic carcinoid discovered following prophylactic thymectomy, both cases demonstrating the weakness and strength of this surgical approach. We then review the spectrum of germline MEN1 mutations associated with thymic carcinoids to evaluate the possibility of a genotype-phenotype correlation. In the 22 separate MEN1 families with thymic carcinoids, all but two (91%) have mutations coding for a truncated protein. There is clearly a high prevalence of truncating mutations in MEN1-related thymic carcinoids although when compared with the prevalence of truncating mutations in all reported MEN1 mutations, it is not statistically significant (P = 0.39). Further studies are warranted to evaluate pathways of tumorigenesis of thymic carcinoids with regard to loss of function of menin.

Primary hyperparathyroidism associatiated with aldosterone-producing adrenocortical adenoma and breast cancer: relation to MEN1 gene

A rare case of primary hyperparathyroidism associated with primary aldosteronism and breast cancer is reported. A 44-year-old woman was admitted to our hospital to undergo surgical removal of breast cancer. She had hypertension with low serum potassium, and slightly but significantly elevated serum calcium levels. Further studies demonstrated an enlarged left superior parathyroid gland and a left aldosterone-producing adrenocortical adenoma. Blood pressure was controlled with spironolactone and nifedipine, and left mastectomy was done for breast cancer. The pathological diagnosis was scirrhous breast carcinoma. Although the postoperative course was uneventful, her serum calcium gradually and progressively rose to higher levels. Left superior parathyroidectomy and left adrenalectomy were then performed simultaneously. The pathological diagnoses of the resected parathyroid gland and adrenal gland were parathyroid chief cell adenoma and adrenocortical adenoma with hyperplasia of zona glomerulosa, respectively. To clarify if the occurence of these tumors may be related to MEN1 gene mutations, we analyzed MEN1 gene in this patient, and found a loss of heterozygosity of the MEN1 locus in the parathyroid adenoma and breast cancer. Thus, we conclude that an alteration of the MEN1 gene and/or another tumor suppressor gene located at the MEN1 locus on chromosome 11q13 may be responsible for the development of parathyroid adenoma and breast cancer in our patient suggesting that the clinical spectrum of MEN1 might include breast cancer. In addition, serum calcium should be interpreted with caution in primary aldosteronism, because hypercalcemia may be masked in the presence of aldosterone excess.

Prospective study of thymic carcinoids in patients with multiple endocrine neoplasia type 1

Little is known of the natural history of thymic carcinoids in multiple endocrine neoplasia type 1 (MEN1). This is important because in 1993 they were identified as a frequent cause of death, yet only small retrospective studies and case reports exist. We report results of a prospective study of 85 patients with MEN1 evaluated for pancreatic endocrine tumors and followed over a mean of 8 yr with serial chest computed tomography, magnetic resonance imaging (MRI), chest x-ray, and, since 1994, octreoscans [somatostatin receptor scintigraphy (SRS)]. Seven patients (8%) developed thymic carcinoids. Patients with and without carcinoids did not differ in clinical, laboratory, or MEN1 tumor features, except for male gender and the presence of a gastric carcinoid. All thymic tumors were hormonally inactive. Four thymic carcinoids lacked 11q loss of heterozygosity, although it was found in three pancreatic endocrine tumors. Computed tomography and/or MRI were more sensitive than SRS or chest x-ray in detecting tumors initially or with recurrence. All patients underwent resection of the thymic carcinoid, and in all patients followed more than 1 yr, the tumor recurred. Bone metastases developed in two patients and were detected early only on MRI, not SRS. This study provides information on early thymic carcinoids and allows modifications of existing guidelines to be recommended for their diagnosis, surveillance, and treatment.

Frequent occurrence of an intron 4 mutation in multiple endocrine neoplasia type 1

MEN1 is an autosomal dominant disorder characterized by parathyroid, pituitary, and pancreatic tumors. The MEN1 gene is located on chromosome 11q13 and encodes a 610-amino acid protein. MEN1 mutations are of diverse types and are scattered throughout the coding region, such that almost every MEN1 family will have its individual mutation. To further characterize such mutations we ascertained 34 unrelated MEN1 probands and undertook DNA sequence analysis. This identified 17 different mutations in 24 probands (2 nonsense, 2 missense, 2 in-frame deletions, 5 frameshift deletions, 1 frameshift deletional-insertion, 3 frameshift insertions, 1 donor splice site mutation, and a g-->a transition that resulted in a novel acceptor splice site in intron 4). The intron 4 mutation was found in 7 unrelated families, and the tumors in these families varied considerably, indicating a lack of genotype-phenotype correlation. However, this intron 4 mutation is the most frequently occurring germline MEN1 mutation ( approximately 10% of all mutations), and together with 5 others at codons 83-84, 118-119, 209-211, 418, and 516, accounts for 36.6% of all mutations, a finding that indicates an approach for identifying the widely diverse MEN1 mutations.

Clinical aspects of hyperparathyroidism in Japanese multiple endocrine neoplasia type 1

We describe here the clinical aspects of hyperparathyroidism (HP) in Japanese multiple endocrine neoplasia type 1 (MEN 1). The total number of MEN 1 patients was 37, and they originated from ten unrelated Japanese families. Nine of the ten families were proven to have heterozygous germline mutations of the MEN 1 gene. The incidence of HP, pituitary tumors, and pancreatic tumors in 37 MEN 1 patients was 91.9%, 32.4%, and 45.9%, respectively. The age-related penetrances of HP were 50%, 79%, 84%, by 20, 30, and 40 years of age, respectively. Of these MEN 1 patients, we used 28 individuals, diagnosed with HP at our hospitals, to study the clinical aspects of MEN 1-associated HP. The mean age was 40 years, and the mean was much lower in the sporadic (non-MEN 1) HP patients. The mean levels of calcium, phosphate, and intact PTH were 10.8 mg/dL, 2.3 mg/dL, and 178.0 pg/mL, respectively, and these were not different from those of sporadic HP patients. The levels of intact PTH were positively correlated with age, suggesting that HP may be progressive with time in MEN 1. The percentage of symptomatic HP was 36% in MEN 1, whereas it was 55% in sporadic HP patients. Although histopathological findings revealed that all four parathyroid glands were involved in hyperplasia, imaging studies showed an enlargement of only the single parathyroid gland in most patients. The combination of total parathyroidectomy and autoplantation succeeding in improving HP in MEN 1.