MEN 2 syndrome masquerading as MEN 1
ABSTRACT Patients with multiple endocrine neoplasia (MEN) type 2A develop medullary thyroid cancer, which is associated with poor prognosis in its metastatic stage. Hyperparathyroidism is a common finding in both MEN 1 and 2. We report a 68-year-old patient diagnosed clinically with MEN 1 based on the presence of hyperparathyroidism and pituitary Cushing's disease with no supporting genetic evidence. The hyperparathyroidism was later found to be part of MEN 2A with underlying metastatic medullary thyroid cancer. We highlight the importance of genetic confirmation before a diagnosis of MEN 1 is made as other more serious pathologies might be overlooked.
Full-textDOI: · Available from: Tarek Ezzat, Apr 15, 2014
- Journal of Clinical Endocrinology & Metabolism 03/1997; 82(2):357-64. · 6.31 Impact Factor
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ABSTRACT: Multiple endocrine neoplasia type 1 (MEN1) is a familial tumour syndrome of endocrine tumours involving parathyroids, anterior pituitary and enteropancreatic neuroendocrine tissues, and is inherited in an autosomal dominant manner with high penetrance. Recently, the gene responsible for this syndrome, MEN1, was positionally cloned from chromosome 11q13. To characterize sporadic MEN1 patients, we analysed the MEN1 gene by direct sequencing of the entire open reading frame from 20 individuals. We identified heterozygous germline mutations of the MEN1 gene in 8 of 20 (40%) cases. Seven were novel MEN1 germline mutations. Three mutations were splicing abnormalities, and all were confirmed to be splicing defects by RT-PCR. The clinical significance of detecting germline MEN1 mutations, not only in familial MEN1 but also in sporadic MEN1, was confirmed by the finding of asymptomatic mutant carriers among family members of the sporadic MEN1 patients. Seven of 8 cases with MEN1 mutations had enteropancreatic lesions in contrast to 4 of 12 (P < 0.018) in those cases with no mutation. Ten of the 12 cases without MEN1 mutation were more than 50-year-old. Six of these 10 cases had the same clinical features; primary hyperparathyroidism and a GH-secreting pituitary tumour. It is likely that the six cases without mutations were MEN1 phenocopies due to (i) two kinds of tumours with high natural incidence in older subjects developed by chance (ii) another familial tumour syndrome with low penetrance, e. g. familial acromegaly with primary hyperparathyroidism by mutation of another gene, or (iii) somatic mutation during early embryonic stages.Clinical Endocrinology 05/2000; 52(4):509-18. DOI:10.1046/j.1365-2265.2000.00966.x · 3.35 Impact Factor
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ABSTRACT: Germline mutations of the RET proto-oncogene are responsible for multiple endocrine neoplasia type 2, including multiple endocrine type 2A (MEN 2A), type 2B (MEN 2B), and familial medullary thyroid carcinoma. The relationship between specific mutations and syndromic features has been established. In particular, the risk for pheochromocytoma and hyperparathyroidism (HPT) in MEN 2A patients is clearly associated with the presence of the RET mutation at a specific position, i.e. at codon 634. Also, a correlation between a specific mutation, C634R, and the development of HPT has been suggested but is still controversial. To further investigate the relationship between specific mutations of codon 634 and the development of HPT, we studied a population of 188 individuals, carrying mutations at codon 634, namely C634R (65 patients belonging to 10 families), C634Y (80 patients belonging to 11 families), or the less frequent codon 634 mutations [i.e. C634S, C634F, C634G, or C634W (43 patients belonging to 9 families)]. In this series of patients, we defined an overall HPT prevalence of 19.1% and found that this prevalence did not vary significantly, with respect to the nature of the mutation. However, irrespective of the particular mutation, the prevalence of HPT showed a high interfamilial variability. The statistical model that best fitted with the observed data was in favor of the heterogeneity of the risk for HPT, with 40% of the families showing an HPT risk of 34% and 60% of the families showing an HPT risk of 9%. In addition, our study clearly demonstrated that HPT could be an early component of the disease and provided the first estimate of age-specific and mutation-specific HPT penetrance in individuals with mutations of codon 634 of the RET proto-oncogene.Journal of Clinical Endocrinology & Metabolism 03/1998; 83(2):487-91. · 6.31 Impact Factor