Reporte de caso de feocromocitoma bilateral asociado a mutación del gen TMEM127. Primer caso chileno / Bilateral pheochromocytoma associates with TMEM127 gene mutation. Report of one case

Up to 40% of Pheochromocytoma/paraganglioma syndromes are associated with germline mutations. Therefore, they are considered familial and heritable. We report a 65 year old woman with hypertension, bilateral adrenal nodules found in the CT scan and elevated urinary metanephrines. Her genetic testing showed a c.117_120delGTCT TMEM127 gene mutation. She was subjected to a laparoscopic bilateral adrenal excision. After five years of follow up, no recurrence of the disease has been recorded.

Pheochromocytoma and paraganglioma: implications of germline mutation investigation for treatment, screening, and surveillance

ABSTRACT Objective Paraganglioma (PGL) and pheochromocytoma (PCC) are rare neuroendocrine tumors that were considered to be predominantly sporadic. However, with the identification of novel susceptibility genes over the last decade, it is currently estimated that up to 40% of cases can occur in the context of a hereditary syndrome. We aimed to characterize PGL/PCC families to exemplify the different scenarios in which hereditary syndromes can be suspected and to emphasize the importance for patients and their families of making an opportune genetic diagnosis. Materials and methods Retrospective analysis of patients diagnosed with PGL/PCC. Germline mutations were studied using next-generation sequencing panels including SDHA, SDHB, SDHC and SDHD. Clinical data were collected from clinical records, and all patients received genetic counseling. Results We describe 4 families with PGL/PCC and germline mutations in SDH complex genes. 2 families have SDHB mutations and 2 SDHD mutations. The clinical presentation of the patients and their families was heterogeneous, with some being atypical according to the literature. Conclusions PGL/PCC are more commonly associated with a germline mutation than any other cancer type, therefore, all individuals with these types of tumors should undergo genetic risk evaluation. NGS multigene panel testing is a cost-effective approach given the overlapping phenotypes. Individuals with germline mutations associated with PGL/PCC should undergo lifelong clinical, biochemical and imaging surveillance and their families should undergo genetic counseling. For all these reasons, it is critical that all medical staff can suspect and diagnose these inherited cancer predisposition syndromes.

What determines mortality in malignant pheochromocytoma? - Report of a case with eighteen-year survival and review of the literature

SUMMARY Pheochromocytoma (PCC) is a tumor derived from adrenomedullary chromaffin cells. Prognosis of malignant PCC is generally poor due to local recurrence or metastasis. We aim to report a case of malignant PCC with 18-year survival and discuss which factors may be related to mortality and long-term survival in malignant pheochromocytoma. The patient, a 45-year-old man, reported sustained arterial hypertension with paroxysmal episodes of tachycardia, associated with head and neck burning sensation, and hand and foot tremors. Diagnosis of PCC was established biochemically and a tumor with infiltration of renal parenchyma was resected. No genetic mutation or copy number variations were identified in SDHB, SDHD, SDHC, MAX and VHL. Over 18 years, tumor progression was managed with 131I-MIBG (iodine-metaiodobenzylguanidine) and 177Lutetium-octreotate therapy. Currently, the patient is asymptomatic and presents sustained stable disease, despite the presence of lung, para-aortic lymph nodes and femoral metastases. Adequate response to treatment with control of tumor progression, absence of significant cardiovascular events and other neoplasms, and lack of mutations in the main predisposing genes reported so far may be factors possibly associated with the prolonged survival in this case. Early diagnosis and life-long follow-up in patients with malignant pheochromocytoma are known to be crucial in improving survival.

Germline gene testing of the RET, VHL, SDHD and SDHB genes in patients with pheochromocytoma/paraganglioma / 北京大学学报(医学版)

OBJECTIVE@#To analyze the germline variations of genes RET, VHL, SDHD and SDHB in patients with pheochromocytoma and/or paraganglioma and to evaluate variations of these genes in Chinese patients.@*METHODS@#Patients who were treated in Peking University First Hospital from September 2012 to March 2014 and diagnosed with pheochromocytoma and/or paraganglioma by pathologists were included in this study. Twelve patients were included in total, of whom 11 had pheochromocytoma, and 1 had paraganglioma. Deoxyribonucleic acid (DNA) was extracted from the leukocytes of peripheral blood of the patients. The exons 10, 11, 13-16 of the RET gene, and all exons of VHL, SDHB and SDHD genes and their nearby introns (±20 bp) were amplified with polymerase chain reactions, and the products were sent to a biotechnology company for sequencing. The sequencing results were compared with wildtype sequences of these genes to identify variations. One of the patients was diagnosed with multiple endocrine neoplasia type 2A. A family analysis was performed in his kindred, and his family members received genetic tests for the related variations.@*RESULTS@#Three patients were found to have germline gene variations. A c.136C>T (p.R46X) variation of the SDHB gene was found in a patient with malignant pheochromocytoma. A c.1901G>A (C634Y) variation, as well as c.2071G>A (p.G691S) and c.2712C>G (p.S904S) variations of the RET gene were found in a patient with multiple endocrine neoplasia type 2A. After a family analysis, five family members of this patient were found to have the same variations. c.2071G>A (p.G691S) and c.2712C>G (p.S904S) variations of the RET gene were also found in a clinical sporadic patient without evidence of malignancy. A patient with congenital single ventricle malformation and pheochromocytoma was included in this study, and no variation with clinical significance was found in the four genes of this patient.@*CONCLUSION@#25% (3/12) patients with pheochromocytoma or paraganglioma were found to have missense or nonsense germline gene variations in this study, including the c.136C>T (p.R46X) variation of the SDHB gene, the c.1901G>A (C634Y) variation of the RET gene, and c.2071G>A (p.G691S) and c.2712C>G (p.S904S) variations of the RET gene. The former two variations have already been confirmed to be pathogenic. The existence of these variations in Chinese patients with pheochromocytoma and/or paraganglioma was validated in this study, which supports the conclusion that genetic testing is necessary to be generally performed in patients with pheochromocytoma and/or paraganglioma.

The clinical genetics of phaeochromocytoma and paraganglioma

ABSTRACT Phaeochromocytoma and paraganglioma are rare catecholamine-producing tumours, recognised to have one of the richest hereditary backgrounds of all neoplasms, with germline mutations seen in approximately 30% of patients. They can be a part of genetic syndromes such as MEN 2 or Neurofibromatosis type 1, or can be found as apparently sporadic tumours. Germline mutations are almost always found in syndromic patients. Nonetheless, apparently sporadic phaeochromocytoma too show high germline mutation rates. Early detection of a genetic mutation can lead to early diagnosis of further tumours via surveillance, early treatment and better prognosis. Apart from this, the genetic profile has important relevance for tumour location and biochemical profile, and can be a useful predictor of future tumour behaviour. It also enables family screening and surveillance. Moreover, recent studies have demonstrated significant driver somatic mutations in up to 75% of all tumours. Arch Endocrinol Metab. 2017;61(5):490-500

Manejo clínico y quirúrgico de los feocromocitomas y paragangliomas / Clinical and surgical management of pheochromocytomas and paragangliomas

Los feocromocitomas y paragangliomas (Feo/PGL) son tumores neurendocrinos raros con diferentes presentaciones clínicas, asociados a alta morbimortalidad. Reconocer los signos y síntomas es el paso diagnóstico inicial. Las metanefrinas fraccionadas urinarias tienen una excelente sensibilidad y especificidad. La tomografía computarizada (TC) es el método de elección para su localización. La tomografía por emisión de positrones (PET) con F18-fluordeoxiglucosa (F18-FDG) es el método funcional recomendado para detectar metástasis. La resección quirúrgica constituye la única opción curativa en estos pacientes. La adrenalectomía laparoscópica es la vía de abordaje para la mayoría los Feo/PGL. El tratamiento farmacológico, 7 a 14 días previos con alfabloqueantes y betabloqueantes, tiene como objetivo normalizar la presión arterial y prevenir complicaciones cardiovasculares periquirúrgicas. Se conoce que al menos un tercio de los pacientes presentan una mutación genética germinal. El estudio genético debe estar orientado a las características sindrómicas, formas de presentación, localización y fenotipo bioquímico del tumor. Se recomienda el abordaje interdisciplinario en centros especializados con experiencia en esta patología poco frecuente. (AU)

Pheochromocytomas and paragangliomas are rare neuroendocrine tumors with different clinical manifestation associated with high morbidity and mortality. Recognize signs and symptoms is the first step in diagnosis. Urinary fractionated metanephrines have an excellent specificity and sensitivity. Computed Tomography (CT) is the first-choice imaging modality for location. F18-DG positron tomography (PET)/CT scanning is the functional modality of choice for metastatic disease. Surgery is the only curative treatment. Minimally invasive adrenalectomy is the surgical approach for most adrenal pheochromocytomas. Perioperative alpha and beta blockade for 7 to 14 days normalize blood pressure and prevent perioperative cardiovascular complications. Is recognize that at least one-third of the patients have disease-causing germline mutations. Genetic testing must be orientated to syndromic features, presentation, localization and biochemical profile of these tumors. Multidisciplinary teams at centers with appropriate expertise are recommended to ensure a favorable outcome. (AU)

Análise do gene CDKN1B/p27kip1 em pacientes com neoplasia endócrina múltipla tipo 2 / CDKN1B/p27kip1 gene analysis in patients with multiple endolcrine neopasia type 2 (MEN2)

INTRODUÇÃO: Na Neoplasia Endócrina Múltipla tipo 2 (NEM2), o desenvolvimento do Carcinoma Medular de Tireoide (CMT), Feocromocitoma (FEO) e Hiperparatireoidismo primário (HPT) está associado à mutações germinativas ativadoras no proto-oncogene RET. Casos de CMT esporádico podem apresentar mutações somáticas no RET (~40%). A variabilidade fenotípica observada em casos de CMT e FEO familiais associados à NEM2 indica o envolvimento de eventos genéticos adicionais que seriam responsáveis pelas diferenças clínicas observadas nos indivíduos afetados (idade de desenvolvimento, progressão e agressividade do tumor). Outras alterações genéticas no RET como duplas mutações, SNPs e haplótipos específicos podem influenciar na susceptibilidade, agressividade e modulação do fenótipo NEM2. Entretanto, os estudos de outros genes envolvidos no processo da tumorigênese NEM2 ainda estão em andamento. Recentemente foi mostrado que RET ativado controla a expressão de proteínas inibidoras do ciclo celular (p18 e p27). Mutações germinativas no gene p27 foram recentemente associadas à susceptibilidade de tumores neuroendócrinos e estão associadas à síndrome NEM4 (Neoplasia endócrina múltipla tipo 4). Mutações somáticas, inativadoras de p27, são raramente encontradas em vários tipos de tumores. Entretanto, diversos estudos documentaram que a redução na expressão e a sublocalização citoplamática de p27 são controladas por alterações pós-transducionais e/ou epigenéticas. OBJETIVOS: o estudo teve como objetivos avaliar a participação de genes, recentemente associados ao RET ativado, em tumores de pacientes com NEM2 e também verificar se polimorfismos no gene p27 estariam atuando como moduladores de fenótipo em uma grande família com NEM2. CASUÍTICA: foram analisadas 66 amostras tumorais advindas de 36 pacientes com diagnóstico clínico e genético de NEM2 e 28 indivíduos pertencentes a uma grande família com NEM2A-CMTF e mutação C620R no gene RET. MÉTODOS:...

INTRODUCTION: In Multiple Endocrine Neoplasia type 2 (MEN2) the development of medullary thyroid carcinoma (MTC), pheochromocytoma (PHEO) and primary hyperparathyroidism (HPT) are associated with activating germline mutations in RET proto-oncogene. Cases of sporadic MTC may have somatic RET mutations (~ 40%). The phenotypic variability observed in cases with familial MTC/MEN2 and PHEO/MEN2 indicates the probable involvement of additional genetic events that could be responsible for the clinical differences observed in the affected individuals (age development, progression and aggressiveness of the tumor). Other genetic alterations such as RET double mutations, SNPs and specific haplotypes may influence susceptibility, aggressiveness and MEN2 phenotype modulation. However, studies of other genes involved in the tumorigenesis of MEN2 are still in progress. Recently, it was shown that the activated RET controls the expression of cell cycle inhibitory proteins (p18 and p27). Germline mutations in the p27 gene have recently been associated with the susceptibility to neuroendocrine tumors and are associated with the MEN4 syndrome (Multiple endocrine neoplasia type 4). Somatic inactivating mutations p27 are rarely found in many types of tumors. However, several studies have documented that reduced expression and subcellular location of p27 is controlled by post-transductional changes and/or epigenetic factors. OBJECTIVES: This study aimed to evaluate the role of genes recently associated with RET activated in tumors from MEN2 patients and also check whether polymorphisms in the p27 gene would be acting as modulators of phenotype in a large MEN2 family. PATIENTS: We analyzed 66 tumor samples from 36 patients with clinical and genetic diagnosis of MEN2 and from 28 individuals belonging to a large family with FMTC/MEN2A and RET C620R mutation. METHODS: The analyses of somatic p27, p15, p18 and RET...

Genetic studies in a coexistence of acromegaly, pheochromocytoma, gastrointestinal stromal tumor (GIST) and thyroid follicular adenoma / Estudos genéticos na coexistência de acromegalia, feocromocitoma, tumor do estroma gastrointestinal (GIST) e adenoma folicular de tireoide

We report on an adult woman with rare coexistence of acromegaly, pheochromocytoma (PHEO), gastrointestinal stromal tumor (GIST), intestinal polyposis, and thyroid follicular adenoma. At the age of 56, she was diagnosed with acromegaly caused by a pituitary macroadenoma, treated by transsphenoidal surgery, radiotherapy, and octreotide. During routine colonoscopy, multiple polyps were identified as tubular adenomas with high-grade dysplasia on histology. Years later, an abdominal mass of 8.0 x 6.2 cm was detected by routine ultrasound. Surgical exploration revealed an adrenal mass and another tumor adhered to the lesser gastric curvature, which were removed. Pathology confirmed the diagnosis of PHEO and GIST. PHEO immunohistochemistry was negative for GHRH. During follow-up, nodular goiter was found with normal levels of calcitonin and inconclusive cytology. Near-total thyroidectomy was performed, revealing a follicular adenoma. Her family history was negative for all of these tumor types. Genetic analysis for PHEO/paraganglioma genes (SDH A-D, SDHAF2, RET, VHL, TMEM127, and MAX), and pituitary-related genes (AIP, MEN1, and p27) were negative. Though the finding of PHEO and acromegaly with multiple other tumors could be a fortuitous coexistence, we suggest that this case may represent a new variant of MEN syndrome with a de novo germline mutation in a not yet identified gene. Arq Bras Endocrinol Metab. 2012;56(8):507-12.

Relatamos o caso de uma mulher com rara coexistência de acromegalia, feocromocitoma (FEO), tumor do estroma gastrointestinal (GIST), polipose intestinal e adenoma folicular de tireoide. Aos 56 anos, ela foi diagnosticada com acromegalia por um macroadenoma hipofisário, tratado com cirurgia transesfenoidal, radioterapia e octreotide. Uma colonoscopia de rotina detectou múltiplos pólipos, que à histologia eram adenomas tubulares com alto grau de displasia. Anos mais tarde, uma ecografia detectou uma massa abdominal de 8.0 x 6.2 cm, que na exploração cirúrgica era uma lesão adrenal e outro tumor aderido à pequena curvatura gástrica. A patologia confirmou os diagnósticos de FEO e GIST. A imuno-histoquímica do FEO foi negativa para GHRH. No seguimento, encontrou-se um bócio nodular com níveis normais de calcitonina e citologia inconclusiva. Após tireoidectomia total o diagnóstico histológico foi de adenoma folicular. A história familiar era negativa para todos esses tumores. As análises genéticas para genes de síndromes de FEO/paragangliomas (SDH A-D, SDHAF2, RET, VHL, TMEM127 e MAX) e para hipofisárias (AIP, MEN1 e p27) foram todas negativas. Embora a presença de FEO e acromegalia com múltiplos outros tumores possa ser uma coexistência fortuita, acreditamos na possibilidade de uma nova variante de NEM com uma mutação germinativa de novo em um gene ainda não identificado Arq Bras Endocrinol Metab. 2012;56(8):507-12.

Over-representation of the G12S polymorphism of the SDHD gene in patients with MEN2A syndrome

OBJECTIVE: To evaluate whether germline variants of the succinate dehydrogenase genes might be phenotypic modifiers in patients with multiple endocrine neoplasia type 2. Mutations of genes encoding subunits of the succinate dehydrogenase are associated with hereditary paraganglioma/pheochromocytoma syndrome. Pheochromocytoma is one of the main manifestations of multiple endocrine neoplasia type 2 caused by germline mutation of the rearranged during transfection proto-oncogene. METHODS: Polymorphisms of the succinate dehydrogenase genes were analyzed in 77 rearranged during transfection mutation carriers, 47 patients with sporadic medullary thyroid cancer, 48 patients with sporadic Pheo, and 100 healthy individuals. Exons 10-16 of the rearranged during transfection proto-oncogene were analyzed by direct DNA sequencing, and all exons of the von Hippel-Lindau, succinate dehydrogenase B, and succinate dehydrogenase subunit D genes were tested by direct DNA sequencing and multiple ligation probe analysis. The G12S polymorphism of the succinate dehydrogenase subunit D gene was determined by restriction fragment length polymorphism. RESULTS: Of the 77 rearranged during transfection mutation carriers, 55 from 16 families had multiple endocrine neoplasia type 2A, three from three families had multiple endocrine neoplasia type 2B, and 19 from two families had familial medullary thyroid carcinoma. Eight of 55 (14.5%) patients with multiple endocrine neoplasia type 2A had this variant whereas it was absent in multiple endocrine neoplasia type 2B, familial medullary thyroid carcinoma, sporadic medullary thyroid carcinoma, and sporadic pheochromocytoma groups, and its prevalence in controls was 1% (p<0.002 multiple endocrine neoplasia type 2A versus controls). No associations between G12S and age of manifestation, incidence of pheochromocytoma or hyperparathyroidism, or level of serum calcitonin were observed. CONCLUSION: The high prevalence of the G12S variant in patients with multiple endocrine neoplasia type 2A raises questions about its role as a genetic modifier, but this proposal remains to be established.

Personalized medicine: caught between hope, hype and the real world

Genomic and personalized medicine have become buzz phrases that pervade all fields of medicine. Rapid advances in "-omics" fields of research (chief of which are genomics, proteinomics, and epigenomics) over the last few years have allowed us to dissect the molecular signatures and functional pathways that underlie disease initiation and progression and to identify molecular profiles that help the classification of tumor subtypes and determine their natural course, prognosis, and responsiveness to therapies. Genomic medicine implements the use of traditional genetic information, as well as modern pangenomic information, with the aim of individualizing risk assessment, prevention, diagnosis, and treatment of cancers and other diseases. It is of note that personalizing medical treatment based on genetic information is not the revolution of the 21st century. Indeed, the use of genetic information, such as human leukocyte antigen-matching for solid organ transplantation or blood transfusion based on ABO blood group antigens, has been standard of care for several decades. However, in recent years rapid technical advances have allowed us to perform high-throughput, high-density molecular analyses to depict the genomic, proteinomic, and epigenomic make-up of an individual at a reasonable cost. Hence, the so-called genomic revolution is more or less the logical evolution from years of bench-based research and bench-to-bedside translational medicine.

Multiple endocrine neoplasia type 2: achievements and current challenges

Incremental advances in medical technology, such as the development of sensitive hormonal assays for routine clinical care, are the drivers of medical progress. This principle is exemplified by the creation of the concept of multiple endocrine neoplasia type 2, encompassing medullary thyroid cancer, pheochromocytoma, and primary hyperparathyroidism, which did not emerge before the early 1960s. This review sets out to highlight key achievements, such as joint biochemical and DNA-based screening of individuals at risk of developing multiple endocrine neoplasia type 2, before casting a spotlight on current challenges which include: (i) ill-defined upper limits of calcitonin assays for infants and young children, rendering it difficult to implement the biochemical part of the integrated DNA-based/biochemical concept; (ii) our increasingly mobile society in which different service providers are caring for one individual at various stages in the disease process. With familial relationships disintegrating as a result of geographic dispersion, information about the history of the origin family may become sketchy or just unavailable. This is when DNA-based gene tests come into play, confirming or excluding an individual's genetic predisposition to multiple endocrine neoplasia type 2 even before there is any biochemical or clinical evidence of the disease. However, the unrivaled molecular genetic progress in multiple endocrine neoplasia type 2 does not come without a price. Screening may uncover unknown gene sequence variants representing either harmless polymorphisms or pathogenic mutations. In this setting, functional characterization of mutant cells in vitro may generate helpful ancillary evidence with regard to the pathogenicity of gene variants in comparison with established mutations.

Enfermedad de von Hippel Lindau en una familia chilena: diagnóstico clínico y genético / Von Hippel Lindau disease: report of an affected family

Von Hippel Lindau disease is a hereditary syndrome characterized by the appearance of benign and malignant tumors in different organs. Its incidence is 1 case per 36000 born alive. We report a family with the disease. The index case was a male with a bilateral pheochromocytoma and cerebelar and retinal hemagioblastomas that had a sudden death due to a cerebrovascular accident at the age of 52 years. One sibling had central nervous system and retinal hemangioblastomas and other was operated for an unilateral pheochromocytoma. Both siblings had the R167Q VHL mutation of the syndrome. Other family members did not have the mutation.

Integrative epigenomic and genomic analysis of malignant pheochromocytoma

Epigenomic and genomic changes affect gene expression and contribute to tumor development. The histone modifications trimethylated histone H3 lysine 4 (H3K4me3) and lysine 27 (H3K27me3) are epigenetic regulators associated to active and silenced genes, respectively and alterations of these modifications have been observed in cancer. Furthermore, genomic aberrations such as DNA copy number changes are common events in tumors. Pheochromocytoma is a rare endocrine tumor of the adrenal gland that mostly occurs sporadic with unknown epigenetic/genetic cause. The majority of cases are benign. Here we aimed to combine the genome-wide profiling of H3K4me3 and H3K27me3, obtained by the ChIP-chip methodology, and DNA copy number data with global gene expression examination in a malignant pheochromocytoma sample. The integrated analysis of the tumor expression levels, in relation to normal adrenal medulla, indicated that either histone modifications or chromosomal alterations, or both, have great impact on the expression of a substantial fraction of the genes in the investigated sample. Candidate tumor suppressor genes identified with decreased expression, a H3K27me3 mark and/or in regions of deletion were for instance TGIF1, DSC3, TNFRSF10B, RASSF2, HOXA9, PTPRE and CDH11. More genes were found with increased expression, a H3K4me3 mark, and/or in regions of gain. Potential oncogenes detected among those were GNAS, INSM1, DOK5, ETV1, RET, NTRK1, IGF2, and the H3K27 trimethylase gene EZH2. Our approach to associate histone methylations and DNA copy number changes to gene expression revealed apparent impact on global gene transcription, and enabled the identification of candidate tumor genes for further exploration.

G691S/S904S polymorphism in the RET protooncogene of a 25-year-old medical student with bilateral pheochromocytoma.

The case of a 25-year-old medical student with bilateral pheochromocytoma is described. Following diagnostic testing, tumors were surgically removed. Genetic analysis revealed that the patient is a heterozygote with the following mutations on opposite homologs: G691S (exon 11) and S904S (TCC-TCG, exon 15), suggesting the diagnosis of multiple endocrine neoplasia 2A (MEN2A). A diagnosis of MEN2 would be an indication of thyroidectomy in this patient. Although this mutation is described in the literature, it has no known connection to pheochromocytomas. Therefore, it is unknown whether there is a causal connection between the G691S genotype and the pheochromocytomas in this patient. If so, G691S is to be added to the list of genotypes causing MEN2A. Here, the procedure of sequencing the RET protooncogene is described and a possible association between the G691S genotype and MEN2A is discussed.

Molecular analysis of the Von Hippel-Lindau (VHL) gene in a family with non-syndromic pheochromocytoma: the importance of genetic testing

The two index patients of the family analyzed in this study had undergone bilateral adrenalectomy for pheochromocytomas. This prompted genetic analyses of the probands and seven first-degree relatives. The two pheochromocytoma patients and two additional asymptomatic family members were found to harbor a mutation c496G>T in exon 3 of the VHL gene. The family was then lost to systematic follow-up. Three years after performing the initial genetic evaluation, the sister of the probands, who was known to carry the same VHL germline mutation, was referred to our service after a pregnancy that was complicated by preeclampsia. She reported paroxysms suggestive for pheochromocytoma, but her urinary metanephrines were negative. However, computerized tomography of the abdomen showed an adrenal mass that was also positive on metaiodobenzylguanidine (MIBG) scintigraphy. This study illustrates that molecular analysis of the index patient(s) can lead to the identification of presymptomatic relatives carrying the mutation. Moreover, despite negative urinary metanephrines, the identification of a specific mutation has led to an increased suspicion and detection of a pheochromocytoma in the sister of the probands.

Dois pacientes índices da família analisada neste estudo foram submetidos a adrenalectomia bilateral devido a feocromocitoma. Foi, então, realizado o estudo genético dos pacientes e de sete parentes de primeiro grau. Os dois pacientes com feocromocitoma e dois outros membros assintomáticos da família apresentaram a mutação c496G>T no exon 3 do gene VHL. A família perdeu seguimento médico. Três anos após a realização da avaliação genética, a irmã dos pacientes, portadora da mutação, foi encaminhada para o nosso serviço após uma gestação complicada por pré-eclampsia. Ela referia paroxismos sugestivos de feocromocitoma, mas as metanefrinas urinárias eram negativas. Entretanto, a tomografia computadorizada de abdômen evidenciou uma massa adrenal que também se contrastou na cintilografia com metaiodobenzilguanidina (MIBG). Esse estudo mostra que a análise molecular do paciente índice pode levar à identificação de parentes assintomáticos portadores da mutação. Além disso, mesmo com as metanefrinas urinárias negativas, a identificação de uma mutação específica levou a um aumento da suspeita e detecção de feocromocitoma na irmã dos afetados pela doença.

Study of the RET gene and his implication in thyroid cancer: Morocco case family.

BACKGROUND: Multiple endocrine neoplasia type 2A (MEN 2A) is an autosomal dominant inherited cancer syndrome that affects multiple tissues derived from the neural crest. Inheritance of MTC is related to the presence of specific mutations in the RET proto-oncogene. Almost all mutations in MEN 2A involve one of the cysteines in the extracellular domain of the RET receptor. AIMS: The objective of the present study was the biochemical and molecular characterization of the first Moroccan clinically established MEN 2A patient and at-risk family members. SETTINGS AND DESIGN: This is a study on a family presented with MTC referred to our institute in 2004. MATERIALS AND METHODS: Peripheral blood leukocyte DNA samples were isolated and amplified by polymerase chain reaction followed by restriction enzyme analysis and DNA sequencing. RESULTS: We identified a heterozygous germ line missense mutation at codon 634 of exon 11 in the RET gene that causes a cysteine to arginine amino acid substitution in the DNA of the proband; this mutation was not found in the DNA of the parents or relatives. CONCLUSIONS: The detection of mutated MEN 2A gene carriers enables us to differentiate high-risk members from those who bear the wild-type gene. Occasionally, application of RET proto-oncogene testing may lead to the detection of unexpected de novo mutation that could be transmitted to children.

Impact of RET proto-oncogene analysis on the clinical management of multiple endocrine neoplasia type 2

A neoplasia endócrina múltipla tipo 2 (NEM2) é caracterizada pela ocorrência do carcinoma medular de tireóide (CMT), hiperparatiroidismo primário (HPT) e feocromocitoma (FEO).1-12 Desde 1993, quando as primeiras mutações do tipo missense no proto-oncogene RET (RET), associadas a NEM2 foram identificadas, 46 diferentes mutações causadoras de doenças foram descritas.13-17 Como há uma forte correlação genótipo-fenótipo na NEM2, a detecção de mutações no RET adquiriu grande impacto no tratamento precoce do CMT e NEM2. A NEM2 persiste como uma doença subdiagnosticada e/ou tardiamente diagnosticada em várias áreas geográficas do globo. A análise de mutações do RET deve ser realizada em todas os casos de NEM2 e atualmente, a tireoidectomia total profilática é indicada para todos os indivíduos portadores de mutações no RET.1 Para a grande maioria dos portadores de mutações gaméticas ativadoras no RET este procedimento cirúrgico é indicado nos primeiros anos de vida, promovendo melhora na qualidade de vida, aumento da sobrevida ou mesmo levando à cura definitiva.1 Discutimos nesta revisão, o impacto da análise do proto-oncogene RET na conduta clínica da neoplasia endócrina múltipla tipo 2. Além disso, o diagnóstico molecular do RET fornece à clínicos e cirurgiões a mais valiosa das informações, permitindo indicação de tireoidectomia total profilática.

Neoplasia endócrina múltipla tipo 2 / Multiple endocrine neoplasia type 2

O termo neoplasia endócrina múltipla tipo 2 (NEM 2) foi sugerido em 1968, por Steiner e cols., para diferenciar a síndrome clínica caracterizada pela presença de carcinoma medular de tireóide (CMT), feocromocitoma e hiperparatireoidismo, então denominada síndrome de Sipple, da síndrome de Wermer ou NEM tipo 1, que acomete as glândulas paratireóides, pâncreas e hipófise. Sizemore e cols. (1974) complementaram a diferenciação através da classificação da NEM 2 em 2 subgupos: pacientes com CMT, feocromocitoma, hiperparatireoidismo e aparência normal (NEM 2A) e pacientes sem acometimento das paratireóides e fenótipo caracterizado por ganglioneuromatose intestinal e hábitos marfanóides (NEM 2B). CMT é usualmente o primeiro tumor a ser diagnosticado. O diagnóstico do CMT determina que seja avaliada a extensão da doença e rastreamento do feocromocitoma e hiperparatireoidismo. O diagnóstico de CMT esporádico ou hereditário é realizado através da análise molecular do proto-oncogene RET. Neste artigo são discutidos os aspectos fisiopatológicos, as anormalidades genéticas e os aspectos clínicos da NEM 2. A abordagem diagnóstica e terapêutica nos indivíduos afetados, carreadores assintomáticos e familiares em risco também são discutidos. Os avanços relacionados ao rastreamento genético e intervenção precoce permitiram uma melhoria no prognóstico a longo prazo. No entanto, ainda não dispomos de tratamento eficaz para doença metastática.

A genética das síndromes hipertensivas endócrinas / Genetic aspects of endocrine hypertensive disorders

A hipertensão arterial sistêmica está associada a altos índices de morbi-mortalidade e constitui um dos grandes problemas de saúde pública no mundo, dada sua alta prevalência e baixa porcentagem de controle com os tratamentos adotados. Este último problema é justificado, pelo menos em parte, porque ainda utilizamos medidas empíricas para o tratamento, ao invés de uma abordagem específica para cada caso. Os determinantes primários da hipertensão permanecem desconhecidos na maioria dos pacientes, ao qual damos o nome genérico de hipertensão essencial ou primária. Estas limitações estão alicerçadas pelo conceito de que a hipertensão é uma doença complexa, poligênica em sua maioria e com direta interação com fatores ambientais, tais como dieta, ingestão de sal e obesidade, entre outras. A utilização de técnicas de biologia molecular tem trazido uma enorme contribuição para a compreensão de fenômenos biológicos complexos. Sabe-se que em uma minoria dos casos a hipertensão arterial ocorre pela presença de mutações específicas, ditas formas mendelianas, que resultam em ganho de função de transportadores do néfron distal, bem como de vários componentes do sistema renina-angiotensina-aldosterona com conseqüente retenção excessiva de sal. De interesse particular na endocrinologia, estas síndromes podem ser divididas em aumento na produção ou na atividade dos mineralocorticóides e estarão expostas nesta revisão.

Feocromocitoma / Pheochromocytoma

Apresentamos a experiência do Hospital das Clínicas da FMUSP, com o diagnóstico clínico, laboratorial e topográfico e com o tratamento do feocromocitoma. Embora novos testes bioquímicos, como as determinações de metanefrinas plasmáticas, tenham maior sensibilidade no diagnóstico desse tumor, testes mais disponíveis, como as determinações de metanefrinas urinárias e catecolaminas plasmáticas e urinárias ainda demonstram grande valor no diagnóstico. Eventuais falso-negativos e falso-positivos podem ser identificados com os testes de estímulo e depressão e com a exclusão do uso de droga. A ressonância magnética é o método mais sensível na identificação topográfica do tumor. O tratamento do tumor, exceto quando houver contraindicações, é sempre cirúgico e deve ser precedido pelo tratamento clínico. A identificação desse tumor é de fundamental importância no sentido de se prevenir a ocorrência de eventos com alta morbidade e mortalidade, bem como na identificação de outras síndromes neoplásicas que podem estar associadas a ele.