Most cases of sporadic primary hyperparathyroidism present disturbances in a single parathyroid gland and the surgery of choice is adenomectomy. Conversely, hyperparathyroidism associated with multiple endocrine neoplasia type 1 (hyperparathyroidism/multiple endocrine neoplasia type 1) is an asynchronic, asymmetrical multiglandular disease and it is surgically approached by either subtotal parathyroidectomy or total parathyroidectomy followed by parathyroid auto-implant to the forearm. In skilful hands, the efficacy of both approaches is similar and both should be complemented by prophylactic thymectomy. In a single academic center, 83 cases of hyperparathyroidism/ multiple endocrine neoplasia type 1 were operated on from 1987 to 2010 and our first surgical choice was total parathyroidectomy followed by parathyroid auto-implant to the non-dominant forearm and, since 1997, associated transcervical thymectomy to prevent thymic carcinoid. Overall, 40% of patients were given calcium replacement (mean intake 1.6 g/day) during the first months after surgery, and this fell to 28% in patients with longer follow-up. These findings indicate that several months may be needed in order to achieve a proper secretion by the parathyroid auto-implant. Hyperparathyroidism recurrence was observed in up to 15% of cases several years after the initial surgery. Thus, long-term follow-up is recommended for such cases. We conclude that, despite a tendency to subtotal parathyroidectomy worldwide, total parathyroidectomy followed by parathyroid auto-implant is a valid surgical option to treat hyperparathyroidism/multiple endocrine neoplasia type 1. Larger comparative systematic studies are needed to define the best surgical approach to hyperparathyroidism/multiple endocrine neoplasia type 1.

BACKGROUND: The molecular mechanisms involved in the genesis of the adrenocortical lesions seen in MEN1 syndrome (ACL-MEN1) remain poorly understood; loss of heterozygosity at 11q13 and somatic mutations of MEN1 are not usually found in these lesions. Thus, additional genes must be involved in MEN1 adrenocortical disorders. Overexpression of the glucose-dependent insulinotropic peptide receptor has been shown to promote adrenocortical tumorigenesis in a mice model and has also been associated with ACTH-independent Cushing syndrome in humans. However, to our knowledge, the status of glucose-dependent insulinotropic peptide receptor expression in adrenocortical lesions in MEN1 has not been previously investigated. OBJECTIVE: To evaluate glucose-dependent insulinotropic peptide receptor expression in adrenocortical hyperplasia associated with MEN1 syndrome. MATERIALS/METHODS: Three adrenocortical tissue samples were obtained from patients with previously known MEN1 germline mutations and in whom the presence of a second molecular event (a new MEN1 somatic mutation or an 11q13 loss of heterozygosity) had been excluded. The expression of the glucose-dependent insulinotropic peptide receptor was quantified by qPCR using the DDCT method, and b-actin was used as an endogenous control. RESULTS: The median of glucose-dependent insulinotropic peptide receptor expression in the adrenocortical lesions associated with MEN1 syndrome was 2.6-fold (range 1.2 to 4.8) higher than the normal adrenal controls (p = 0.02). CONCLUSION: The current study represents the first investigation of glucose-dependent insulinotropic peptide receptor expression in adrenocortical lesions without 11q13 loss of heterozygosity in MEN1 syndrome patients. Although we studied a limited number of cases of MEN1 adrenocortical lesions retrospectively, our preliminary data suggest an involvement of glucose-dependent insulinotropic peptide receptor overexpression in the etiology of adrenocortical hyperplasia. New prospective studies will be able to clarify the exact role of the glucose-dependent insulinotropic peptide receptor in the molecular pathogenesis of MEN1 adrenocortical lesions.

A neoplasia endócrina múltipla tipo 2 (NEM2) é uma síndrome tumoral herdada por mutações germinativas no proto-oncogene RET (RET). Analisamos a aplicação do método Eletroforese em Gel Sensível à Conformação (CSGE) no rastreamento de mutações hot spots do RET. Sete famílias com NEM2 foram rastreadas pelo seqüenciamento gênico, CSGE e análise do Polimorfismo Conformacional de Cadeia Simples (SSCP). Usando ambas as metodologias de rastreamento, identificamos quatro dos cinco tipos de mutações verificadas pelo seqüenciamento: Cys620Arg, Cys634Arg, Cys634Tyr e Met918Thr, além da variação gênica Val648Ile. Das análises englobando mutações hot spots do RET, 90,6% concordaram com o seqüenciamento genético (incluindo a variação gênica Val648Ile). Polimorfismos nos códons 691 e 769 foram documentados. Os dados obtidos por CSGE/SSCP foram totalmente concordantes. Concluímos que o CSGE revelou ser metodologia sensível, rápida, de fácil execução e baixo custo no rastreamento de mutações nos códons associados à grande maioria (~ 95%) dos pacientes com NEM2.

Multiple endocrine neoplasia type 2 (MEN2) is an autosomal dominant inherited tumor syndrome caused by RET proto-oncogene germline mutations (RET). Here we tested the Conformation Sensitive Gel Electrophoresis (CSGE) as a screening method for RET hot-spot mutations. Seven MEN2 families were studied by direct sequencing analysis, CSGE and Single Strand Conformational Polymorphism (SSCP). Using CSGE/SSCP, we were able to detect four out of five types of RET mutations verified by sequencing analysis: Cys620Arg, Cys634Arg, Cys634Tyr, and Met918Thr, furthermore a missense substitution at codon 648 (Val648Ile). RET polymorphisms 691 and 769 were also verified. Data obtained using CSGE/SSCP were fully concordant. We conclude that CSGE showed to be a sensitive, fast, low-cost, and simple procedure to detect RET mutations in codons which are reported as the most prevalent RET variants (~ 95%) in large MEN2 series. As to the Val804Met mutation, this method still needs to be optimized.

OBJETIVOS: Realizar rastreamentos clínico e gênico para Neoplasia Endócrina Múltipla tipo 1 (NEM1) e analisar seu impacto no seguimento clínico desses pacientes no Hospital das Clínicas, SP. MÉTODOS: O diagnóstico clínico de NEM1 foi realizado de acordo com o Consenso sobre neoplasias endócrinas múltiplas. A análise genética para identificação de mutações foi realizada por sequenciamento automático de todas as regiões codificadoras e fronteiras exon/intron do gene MEN1. Os casos afetados foram sub-divididos em 3 grupos e analisados separadamente: casos-índices (grupo I), familiares diagnosticados clinicamente (grupo II) e genicamente (grupo III). RESULTADOS: Um total de 154 casos participou desse estudo, sendo 52 diagnosticados com NEM1: 13 do grupo I, 28 do grupo II e 11 do grupo III. A idade média ao diagnóstico no grupo III (27 anos) foi significativamente menor que a dos grupos I (39,5 anos; p = 0,03) e II (42,4 anos; p = 0,01). A maioria dos pacientes dos grupos I e II apresentou 2 ou 3 tumores, enquanto que 81,8% dos casos do grupo III apresentavam 1 ou nenhum tumor relacionado à NEM1. Além disto, 45,4% dos casos do grupo III eram assintomáticos, não sendo observados nenhuma metástase ou óbito. Os demais 102 familiares sob-risco estudados não herdaram mutação MEN1 e foram excluídos do rastreamento clínico. Um caso de fenocópia NEM1 foi também localizado. DISCUSSÃO: Nossos dados demonstraram importantes benefícios no seguimento dos pacientes NEM1, obtidos pela implementação dos rastreamentos clínico e gênico para essa doença.

PURPOSE: To perform clinical and genetic screening for multiple endocrine neoplasia type 1 (MEN1) in patients at the Academic Hospital of the University of São Paulo School of Medicine, and to analyze its impact on clinical management of patients with MEN1. METHODS: The clinical diagnosis of MEN1 was made in accordance with the Consensus on multiple endocrine neoplasias. Mutation analysis of the entire MEN1 tumor suppressor gene and genetic screening of at-risk family members were performed by direct sequencing. To analyze the implementation of genetic diagnosis, the studied patients were separated into 3 groups: MEN1 index cases (group I), clinically diagnosed MEN1 cases (group II), and genetically diagnosed MEN1 cases (group III). RESULTS: In total, 154 individuals were clinically and genetically studied. We identified 12 different MEN1 mutations. Fifty-two MEN1 cases were identified: 13 in group I, 28 in group II, and 11 in group III. The mean age in group III (27.0 years) was significantly lower than in groups I (39.5 years) and II (42.4 years; P = 0.03 and P = 0.01, respectively). Patients in groups I and II mostly presented 2 or 3 MEN1-related tumors, while 81.8% of those in group III presented 1 or no MEN1-related tumor. Additionally, in group III, 45.4% of cases were asymptomatic, and no metastasis or death was verified. Surveillance for MEN1 mutations allowed the exclusion of 102 noncarriers, including a case of MEN1 phenocopy. CONCLUSION: Our data supports the benefits of clinical and genetic screening for multiple endocrine neoplasia type 1 in the management of this syndrome.

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.

Multiple endocrine neoplasia type 2 (MEN2) is an autosomal dominant disease characterized by the presence of medullary thyroid carcinoma, primary hyperparathyroidism, and pheochromocytoma. Multiple endocrine neoplasia type 2 is still an underdiagnosed, or late-diagnosed condition in many areas of the world. Since 1993, when the first missense RET proto-oncogene (RET) mutations were reported in MEN2, up to 46 different RET-causing disease mutations have been described. Since a strong genotype-phenotype correlation exists for MEN2, the detection of RET mutations has produced a major impact in early recognition and treatment of MTC and MEN2. Presently, RET mutation analysis should be performed for all MEN2 cases and their at-risk familial relatives. Further, prophylactic total thyroidectomy is indicated in all cases harboring activating gametic RET mutations. In most RET mutation carriers, prophylactic total thyroidectomy is indicated at ages as early as a few months to 4 years of age, promoting longer survival and improvement of quality of life or even definitive cure. We discuss the large impact of RET proto-oncogene analysis on the clinical management of MEN2 and the role of early RET molecular DNA diagnosis in providing clinicians and surgeons with valuable information that enables them to indicate early total thyroidectomy.