An Intronic mutation is associated with prolactinoma in a young boy, decreased penetrance in his large family, and variable effects on MEN1 mRNA and protein

Giant Prolactinoma Causing Hydrocephalus and Intracranial Hypertension as First Manifestations of Multiple Endocrine Neoplasia Type 1

Context: Overall, giant prolactinomas are rare tumors (4%), especially those larger than 60 mm (1%). Despite the predominance of macroadenoma documented in multiple endocrine neoplasia type 1 (MEN1)-related prolactinoma, only three giant prolactinoma cases were described so far (size > 40 mm and prolactin > 1,000 ng/mL). None of them was larger than 60 mm or presented hydrocephalus or intracranial hypertension (ICH) as initial manifestation of MEN1. Case Description: A 21-years-old man presented with ICH as the first clinical manifestation of MEN1. He harbored a MEN1 germline mutation but refused periodic vigilance after normal hormonal screening at age 14 years. During investigation, magnetic resonance imaging (MRI) of the skull showed an expansive sellar/parasellar lesion (75 × 44 × 36 mm) with moderate to severe supratentorial obstructive hydrocephalus and an extremely high serum prolactin (PRL) of 10,800 ng/mL, without combined hypersecretion of other pituitary hormones. He was diagnosed with giant prolactinoma, and cabergoline was initiated. The patient evolved with early improvement of clinical complaints for hydrocephalus and ICH and PRL reached normal values (11 ng/mL) in association with significant tumoral shrinkage after 18 months on cabergoline. After 2 months of cabergoline, cerebrospinal fluid leakage was diagnosed and corrective surgery was provided. The mean dose of cabergoline was 3 mg/week throughout treatment. Conclusion: We reported the first case with hydrocephalus and ICH as the initial clinical manifestation of a giant prolactinoma in MEN1. From our knowledge, this is the largest MEN1-related prolactinoma reported so far. Notably, all four MEN1-related giant prolactinomas cases reported were younger than 21 years strengthening the importance to routine MEN1 genetic testing for prolactinoma in this age group. Also, they all had initial effective response with dopamine agonist ensuring this drug as first-line treatment for MEN1-related giant prolactinoma. However, the scarce number of treated patients and progression of cabergoline resistance in two of them suggest strict surveillance.

Novel MEN 1 gene findings in rare sporadic insulinoma--a case control study

BACKGROUND

Insulinomas, which are rare tumors causing hyperinsulinemic hypoglycemia are usually sporadic but may also occur in association with multiple endocrine neoplasia type 1 (MEN-1) syndrome an autosomal dominant disorder caused by MEN1 gene mutations. MEN1 encodes a nuclear protein Menin, a tumor suppressor which acts as an adapter and interacts with partner proteins involved in crucial activities like transcriptional regulation, cell division, proliferation and genome stability. This study reports on clinical findings and mutation screening in sporadic insulinoma patients.

METHODS

Seventeen patients diagnosed with insulinoma were recruited along with 30 healthy volunteers who acted as controls for the present study. The patients presented with symptoms of sweating, tremors, drowsiness, palpitations, loss of consciousness, abnormal behavior, seizures and weight gain. Detailed clinical and family history was collected from all the participants along with 5 ml of blood sample after taking informed consent. Genomic DNA isolated from blood was subjected to MEN1 gene amplification followed by direct sequencing. Nucleotide sequences obtained were compared with published MEN1 cDNA sequences. Prediction of functional effects of novel changes was done using various bioinformatics algorithms.

RESULTS

Molecular analysis revealed presence of three novel exonic mutations (M561K, Q192K and Q261Q), two novel intronic variations c.445-44G → A and c.913-42G → C in introns two and six respectively and three reported exon SNPs; H433H (rs540012), D418D (rs2071313), A541T (rs2959656) and one intronic SNP (rs669976).

CONCLUSIONS

The study identified presence of novel pathogenic MEN1 mutations in sporadic cases of insulinoma. The new mutations identified were in regions involved in defective binding of menin to proteins implicated in genetic and epigenetic mechanisms. The outcome of the study extends the growing list of MEN1 pathogenic mutations even in sporadic cases providing consequential insight into phenotypic heterogeneity and in the expression of individual mutations.

Genetic mutations in sporadic pituitary adenomas--what to screen for?

Pituitary adenomas are benign intracranial neoplasms that can result in morbidity owing to local invasion and/or excessive or deficient hormone production. The prevalence of symptomatic pituitary adenomas is approximately 1:1,000 in the general population. The vast majority of these tumours occur sporadically and are not part of syndromic disorders. However, germline mutations in genes known to predispose individuals to familial pituitary adenomas are found in a few patients with sporadic pituitary adenomas. Mutations in AIP (encoding aryl-hydrocarbon receptor-interacting protein) are the most frequently observed germline mutations. The prevalence of these mutations in patients with sporadic pituitary adenomas is ∼4%, but can increase to 8-20% in young adults with macroadenomas or gigantism, and also in children. Germline mutations in MEN1 (encoding menin) result in multiple endocrine neoplasia type 1 and are found in very young patients with isolated sporadic pituitary adenomas, which highlights the importance of the chromosome 11q13 locus in pituitary tumorigenesis. In this Review, we describe the clinical features of patients with sporadic pituitary adenomas that are associated with AIP or MEN1 mutations, and discuss the molecular mechanisms that might be involved in pituitary adenoma tumorigenesis. We also discuss genetic screening of patients with sporadic pituitary adenomas and investigations of relatives of these patients who also have the same genetic mutations.

Standards of care intended for multiple endocrine neoplasia families

In the past, the medical expenditure for multiple endocrine neoplasia families was high and the course of their disease not predictable. In a couple of decades, the prospects changed completely. The genetic origin of the diseases is well known and prevention is possible, whereas in advanced stages target-directed treatment is coming within reach. The most important change is the responsibility for these families. Initially, this was completely the task of the attending physician, whereas at this moment patients and disease gene carriers themselves have the central responsibility with respect to these diseases. Unfortunately, for them information about the disease is insufficiently available.

Clinical and pathological impact of VHL, PBRM1, BAP1, SETD2, KDM6A, and JARID1c in clear cell renal cell carcinoma

VHL is mutated in the majority of patients with clear cell renal cell carcinoma (ccRCC), with conflicting clinical relevance. Recent studies have identified recurrent mutations in histone modifying and chromatin remodeling genes, including BAP1, PBRM1, SETD2, KDM6A, and JARID1c. Current evidence suggests that BAP1 mutations are associated with aggressive disease. The clinical significance of the remaining genes is unknown. In this study, targeted sequencing of VHL and JARID1c (entire genes) and coding regions of BAP1, PBRM1, SETD2, and KDM6A was performed on 132 ccRCCs and matched normal tissues. Associations between mutations and clinical and pathological outcomes were interrogated. Inactivation of VHL (coding mutation or promoter methylation) was seen in 75% of ccRCCs. Somatic noncoding VHL alterations were identified in 29% of ccRCCs and may be associated with improved overall survival. BAP1 (11%), PBRM1 (33%), SETD2 (16%), JARID1c (4%), and KDM6A (3%) mutations were identified. BAP1-mutated tumors were associated with metastatic disease at presentation (P = 0.023), advanced clinical stage (P = 0.042) and a trend towards shorter recurrence free survival (P = 0.059) when compared with tumors exclusively mutated for PBRM1. Our results support those of recent publications pointing towards a role for BAP1 and PBRM1 mutations in risk stratifying ccRCCs. Further investigation of noncoding alterations in VHL is warranted.

A new double substitution mutation in the MEN1 gene: a limited penetrance and a specific phenotype

Multiple endocrine neoplasia type 1 (MEN1) is an autosomal-dominant cancer syndrome that is caused by a germline mutation in the MEN1 gene encoding a tumour-suppressor protein, menin. MEN1 causes a combination of endocrine tumours such as parathyroid adenomas, pituitary adenomas, glucagonomas, gastrinomas, insulinomas, adrenocortical adenomas and non-endocrine tumours. We here present a large MEN1 family where the carriers developed mild hyperparathyroidism, multiple well-differentiated functionally active neuroendocrine tumours of the pancreas and no pituitary tumour. The causal mutation is a new double substitution in the coding region of exon 2 in the MEN1 gene c.[428T>A; 429C>T], p.Leu143His. This new mutation in the MEN1 gene is clinically relevant leading to a limited penetrance and specific phenotype.

Recent results of basic and clinical research in MEN1: opportunities to improve early detection and treatment

Due to the variable expression of multiple endocrine neoplasia type 1 (MEN1), it is difficult to predict the course of the disease. However, knowledge about the normal function of the MEN1 gene product, together with the effects of cellular derangement by subsequent genetic events, has increased considerably. At first, the possible existence of a genotype-phenotype correlation is discussed. Thus, mild- and late-onset phenotypes may be distinguished from more malignant phenotypes depending on the character of the primary MEN1 disease gene mutation. Subsequently, tumor-promoting factors such as gender, additional genetic mutations and ecogenetic factors may contribute to the course of the disease. New developments in management are based on the knowledge and experience of the multidisciplinary teams involved. Finally, the metabolic effects of MEN1 mutations in aged patients are discussed. Early identification of predisposition to the disease, together with knowledge about the natural history of specific mutations, risks of additional mutations and periodic clinical monitoring, allow early treatment and may improve life expectancy and quality of life.

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.

The role of germline AIP, MEN1, PRKAR1A, CDKN1B and CDKN2C mutations in causing pituitary adenomas in a large cohort of children, adolescents, and patients with genetic syndromes

The prevalence of germline mutations in MEN1, AIP, PRKAR1A, CDKN1B and CDKN2CI is unknown among pediatric patients with pituitary adenomas (PA). In this study, we screened children with PA for mutations in these genes; somatic GNAS mutations were also studied in a limited number of growth hormone (GH) or prolactin (PRL)-secreting PA. We studied 74 and 6 patients with either isolated Cushing disease (CD) or GH- or PRL-secreting PA, respectively. We also screened four pediatric patients with CD, and four with GH/PRL-secreting tumors who had some syndromic features. There was one AIP mutation (p.Lys103Arg) among 74 CD patients. Two MEN1 mutations that occurred in patients with recurrent or difficult-to-treat disease were found among patients with CD. There was one MEN1 and three AIP mutations (p.Gln307ProfsX104, p.Pro114fsX, p.Lys241X) among pediatric patients with isolated GH- or PRL-secreting PA and one additional MEN1 mutation in a patient with positive family history. There were no mutations in the PRKAR1A, CDKN1B, CDKN2C or GNAS genes. Thus, germline AIP or MEN1 gene mutations are frequent among pediatric patients with GH- or PRL-secreting PA but are significantly rarer in pediatric CD; PRKAR1A mutations are not present in PA outside of Carney complex.

Genetic screening for multiple endocrine neoplasia syndrome type 1 (MEN-1): when and how

Multiple endocrine neoplasia syndrome type 1 (MEN1) syndrome has benefited from the identification of the gene whose mutations account for the genetic susceptibility to develop endocrine tumors. Asymptomatic MEN1 mutant carriers need to be clearly recognized because the gene-related mutations confer a high risk of multiple primary cancers, occur at younger ages, and affect multiple family members who inherit the cancer-predisposing genetic mutation.