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ABSTRACT: Context:The molecular pathogenesis of primary hyperparathyroidism (PHPT) is still largely unknown. The AIP gene has a major role in the pathogenesis of familial isolated pituitary adenoma.Objective:We evaluated the involvement of the AIP gene in sporadic parathyroid adenomas.Patients and Design:We carried out direct sequencing and multiplex ligation-dependent probe amplification (MLPA) analyses of the AIP gene in a large series of sporadic parathyroid adenomas. Loss of heterozygosity (LOH) at the AIP locus and AIP immunostaining were also performed. Alterations of the MEN1 gene were also studied.Results:A somatic AIP mutation, substitution of arginine with glutamine at codon 304 (R304Q), was identified in two of 132 tumors. The mutation was germline in both cases despite the nonfamilial presentation. Heterozygous AIP large deletions were detected in 29 cases including one of the two mutated tumors, confirming a biallelic inactivation of AIP gene. The AIP mutated tumor with LOH showed a decreased AIP immunostaining compared to normal parathyroid. LOH at the MEN1 locus was found in one-third of tumors, which often shared LOH at the AIP locus. Somatic MEN1 mutations were found in the one of the two AIP-mutated tumors and in 23 parathyroid adenomas. MLPA analysis revealed one large deletion of the MEN1 gene in one case.Conclusions:The AIP gene is rarely involved in parathyroid adenomas, but the germline nature of the mutations suggest that it might predispose to PHPT. MEN1 gene alterations occur in a substantial proportion of sporadic parathyroid adenomas.
The Journal of clinical endocrinology and metabolism 04/2013; · 6.50 Impact Factor
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ABSTRACT: The calcium-sensing receptor (CASR) has an important role in calcium homoeostasis by controlling PTH secretion and renal calcium handling. Inactivating mutations in the CASR gene (HGNC ID: 1514) cause familial hypocalciuric hypercalcaemia (FHH). We present a case of FHH patient to describe a novel mutation in the CASR.
A 34-year-old patient was referred because of recurrent hypercalcaemia after resection of two hyperplastic parathyroids. Extensive evaluation found elevated PTH and low calcium/creatinine clearance ratio. One of her three children had high serum calcium concentrations. Genetic studies were performed by PCR amplification of CASR coding exons and direct sequencing of PCR products. Transient transfection of the wild-type (WT) CASR and the mutant CASR into COS-7 was performed to assess functional impact of the mutation and the capacity of either protein to mediate increases in cellular levels of inositol phosphates (IPs).
CASR sequencing found a previously undescribed heterozygous base substitution, determining a change of threonine to isoleucine at codon 550 (p.T550I) in the sixth exon. In contrast to those transfected with WT CASR, which showed a five- to eightfold increase in total IPs at high levels of calcium, COS-7 cells transfected with the (p.T550I) mutant showed no increase confirming to the inactivating nature of the mutation. COS-7 cells co-transfected with the WT and the (p.T550I) mutant showed an intermediate response suggesting a possible dominant negative effect.
This case report presents a not-yet-described mutation in the cysteine-rich region of the CASR extracellular domain, a mutation with a possible dominant negative effect.
European Journal of Endocrinology 05/2011; 165(2):359-63. · 3.42 Impact Factor
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Laura Giusti,
Filomena Cetani,
Federica Ciregia,
Ylenia Da Valle,
Elena Donadio,
Gino Giannaccini,
Chiara Banti, Elena Pardi,
Federica Saponaro,
Fulvio Basolo,
Piero Berti,
Paolo Miccoli,
Aldo Pinchera,
Claudio Marcocci,
Antonio Lucacchini
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ABSTRACT: Parathyroid tumours are heterogeneous and in some cases the diagnosis may be difficult using histological features. In this study we used a two-dimensional electrophoresis (2D)/mass spectrometry (MS)-based approach to examine the global changes of parathyroid adenoma tissues protein profile compared to the parathyroid normal tissues. Validation of protein expression was performed by immunoblotting using specific antibodies. Ingenuity software was used to identify the biological processes to which these proteins belong and to construct a potential network. A total of 30 proteins were found to be differentially expressed, of which 22 resulted in being over-expressed. Proteins identified by 2D/MS/MS proteomics were classified into functional categories and a major change (≥ 2-fold) in terms of expression was found in proteins involved in response to biotic stimuli, cell organization and signal transduction. After Ingenuity analysis, 14-3-3 ζ/δ appears to be a key protein in the network of parathyroid adenoma, where it is linked to other proteins such as annexin A2, B box and SPRY domain-containing protein (BSPRY), p53 and epidermal growth factor receptor (EGFR). Our results suggest that the proteomic approach was able to differentiate the protein profiles of normal parathyroid and parathyroid adenoma and identify a panel of proteins which are differentially expressed. The functional role of these proteins in the network of intracellular pathways is discussed.
Molecular BioSystems 03/2011; 7(3):687-99. · 3.53 Impact Factor
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Elena Donadio,
Laura Giusti,
Filomena Cetani,
Ylenia Da Valle,
Federica Ciregia,
Gino Giannaccini, Elena Pardi,
Federica Saponaro,
Liborio Torregrossa,
Fulvio Basolo,
Claudio Marcocci,
Antonio Lucacchini
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ABSTRACT: Proteomic research in the field of parathyroid tissues is limited by the very small dimension of the glands and by the low incidence of cancer lesions (1%). Formalin-fixed paraffin-embedded (FFPE) tissue specimens are a potentially valuable resource for discovering protein cancer biomarkers. In this study we have verified the applicability of a heat induced protein extraction from FFPE parathyroid adenoma tissues followed by a gel-based or gel-free proteomic approach in order to achieve protein separation and identification.
The best results for high quality MS spectra and parameters, were obtained by using a gel-free approach, and up to 163 unique proteins were identified. Similar results were obtained by applying both SDS-out and SDS-out + TCA/Acetone techniques during the gel-free method. Western blot analysis carried out with specific antibodies suggested that the antigenicity was not always preserved, while specific immunoreactions were detected for calmodulin, B box and SPRY domain-containing protein (BSPRY), peroxiredoxin 6 (PRDX 6) and parvalbumin.
In spite of some limitations mainly due to the extensive formalin-induced covalent cross-linking, our results essentially suggest the applicability of a proteomic approach to FFPE parathyroid specimens. From our point of view, FFPE extracts might be an alternative source, especially in the validation phase of protein biomarkers when a large cohort of samples is required and the low availability of frozen tissues might be constraining.
Proteome Science 01/2011; 9(1):29. · 2.33 Impact Factor
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Sandro Giannini,
Stefania Sella,
Fatima Silva Netto,
Catia Cattelan,
Luca Dalle Carbonare,
Roberta Lazzarin,
Francesco Marchini,
Paolo Rigotti,
Claudio Marcocci,
Filomena Cetani, Elena Pardi,
Angela D'Angelo,
Giuseppe Realdi,
Luciana Bonfante
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ABSTRACT: Bone morbidity remains a major problem even after successful renal transplantation. We investigated the role of calcium-sensing receptor (CaSR) polymorphisms and 25-hydroxyvitamin D levels on the persistence of secondary hyperparathyroidism (SHPT) and their relationships with vertebral fractures (VFx) in 125 renal allograft recipients transplanted 44 +/- 23 months before. All patients underwent evaluation of the main biochemical parameters of calcium metabolism as well as vertebral and femoral bone density. In 87 patients, CaSR polymorphisms (A986S, R990G, and Q1011E) also were assessed. X-ray images of the lateral spine were obtained in 102 subjects to perform vertebral morphometry. High parathyroid hormone (PTH) and 25-hydroxyvitamin D lower than 80 nmol/L were found in 54% and 97% of patients, respectively, with 40% of these showing vitamin D levels lower than 30 nmol/L. VFx were detected in 57% of the subjects. After multiple adjustments, 25-hydroxyvitamin D, age, and hemodialysis duration, but not CaSR polymorphisms, were found to be significant predictors of high PTH, whereas age and time since transplant were positively related with lower 25-hydroxyvitamin D values. PTH and time since transplant were significantly associated with VFx. Patients with two or more VFx showed serum PTH levels 50% higher than patients without fractures. We therefore conclude that persistent SHPT is a very common feature after renal transplantation and that, unlike CaSR polymorphisms, low 25-hydroxyvitamin D is involved in its pathogenesis. High PTH levels, in turn, are associated with an increased VFx risk, which confirms the need for strategies aimed at lowering serum PTH in this setting as well.
Journal of bone and mineral research: the official journal of the American Society for Bone and Mineral Research 10/2009; 25(4):841-8. · 6.04 Impact Factor
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F Cetani, E Pardi,
C Banti,
P Collecchi,
P Viacava,
S Borsari,
G Fanelli,
A G Naccarato,
F Saponaro,
P Berti,
P Miccoli,
A Pinchera,
C Marcocci
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ABSTRACT: Aberrant accumulation of beta-catenin has been found in various types of human tumors. The aim of this study was to evaluate whether Wnt/beta-catenin signaling is activated in parathyroid carcinomas and adenomas. We studied 154 parathyroid tumors (18 carcinomas (13 with distant metastases), six atypical adenomas, and 130 adenomas). Three normal parathyroid tissues were used as control. Direct sequencing of exon 3 of the CTNNB1 gene showed absence of stabilizing mutations in all the tumors. Immunostaining of beta-catenin was performed in all carcinomas and in 66 adenomas (including three atypical). Normal parathyroid showed a homogeneous distinct outer cell membrane staining in the majority of cells and no nuclear staining. A weak cytoplasmic staining was observed in one case. All tumors showed negative nuclear staining. With the exception of one carcinoma, which had a negative membrane staining, all other samples showed a membrane staining which was similar to that of the normal parathyroid. beta-Catenin expression was heterogeneous with a range of positive cells between 5 and 80%, independently of tumor type. Our results suggest that the Wnt/beta-catenin signaling pathway is not involved in the development of parathyroid carcinomas and adenomas.
Endocrine Related Cancer 09/2009; 17(1):1-6. · 4.36 Impact Factor
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Filomena Cetani,
Monica Lemmi,
Davide Cervia,
Simona Borsari,
Luisella Cianferotti, Elena Pardi,
Elena Ambrogini,
Chiara Banti,
Edward M Brown,
Paola Bagnoli,
Aldo Pinchera,
Claudio Marcocci
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ABSTRACT: Identification and characterization of calcium-sensing receptor (CASR) mutations in four unrelated Italian kindreds with familial hypocalciuric hypercalcemia.
Clinical evaluation and genetic analysis of CASR gene. Functional characterization of mutated CASRs.
Direct sequencing of CASR gene in genomic DNA. Studies of CASR-mediated increases in cytosolic calcium concentration [Ca(2)(+)](i) in CASR-transfected COS-7 cells in vitro.
Four unreported heterozygous CASR mutations were identified, including three missense (H595Y, P748H, and C765W) and one splice site (IVS2+1G>C) mutation. The H595Y, P748H, and C765W mutant receptors, although expressed at normal levels on the cell surface, showed a reduced response in [Ca(2)(+)](i) relative to the wildtype (WT) CASR to increasing extracellular calcium concentrations. Cotransfection experiments showed that the H595Y and P748H mutants did not affect the apparent affinity of the WT CASR for calcium, suggesting that they do not exert a dominant-negative effect. On the other hand, the co-transfected C765W mutant decreased the maximum response of the WT CASR to calcium, suggesting that it may reduce the effective concentration of the normal CASR on the cell surface or impair its maximal signaling capacity.
Four CASR mutations were identified. The reduced functional responses to extracellular calcium and normal expression of the mutant receptors suggest that conformational changes account for altered CASR activity. Moreover, a reduced complement of normal CASRs in these heterozygous patients, perhaps combined with a mutant receptor-induced decrease in maximal activity of the WT receptor, may contribute to defective calcium-sensing in vivo.
European Journal of Endocrinology 12/2008; 160(3):481-9. · 3.42 Impact Factor
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ABSTRACT: Parathyroid carcinoma is an uncommon cause of primary hyperparathyroidism (PHPT) and is usually associated with more severe clinical manifestations than its much more common benign counterpart, the parathyroid adenomas. The histopathological distinction between benign and malignant parathyroid tumors is difficult. Currently, pathological diagnosis of parathyroid carcinoma is restricted to lesions showing unequivocal growth, as evidenced by perineural invasion, full-thickness capsular invasion with growth into adjacent tissues, or metastasis. Major advances in the molecular pathogenesis of parathyroid carcinoma have been made by the cloning of the HRPT2 gene, which encodes parafibromin, a 531-amino acid putative tumor-suppressor protein. Germline mutations of HRPT2 confer susceptibility to the hyperparathyroidism-jaw tumor syndrome (HPT-JT), an autosomal dominant syndrome with high but incomplete penetrance. Somatic inactivating mutations of the HRPT2 gene have been reported in the majority of apparently sporadic parathyroid carcinomas but, unexpectedly, germline HRPT2 mutation have been found in up to 30% of these patients. Several studies have been performed to evaluate whether parafibromin immunostaining might have some diagnostic utility. Loss of parafibromin immunoreactivity has been found in the majority of parathyroid carcinomas, in 50% of equivocal carcinomas and, very rarely, in benign adenomas. On the other hand, with the exception of HPT-JT-related tumors, loss of parafibromin associated with HRPT2 mutations strongly predicts parathyroid malignancy. In clinical practice, parafibromin immunostaining and HRPT2 gene analysis could be particularly useful in the subset of parathyroid tumors with equivocal histology.
Expert Review of Endocrinology & Metabolism 04/2008; 3(3):377-389.
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Filomena Cetani,
Elena Ambrogini,
Paolo Viacava, Elena Pardi,
Giovanni Fanelli,
Antonio Giuseppe Naccarato,
Simona Borsari,
Monica Lemmi,
Piero Berti,
Paolo Miccoli,
Aldo Pinchera,
Claudio Marcocci
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ABSTRACT: HRPT2 gene mutations are associated with parathyroid carcinomas, and absence of parafibromin immunoreactivity has been suggested as a diagnostic marker of malignancy. The aim of our study was to extend parafibromin studies in a series of benign and malignant parathyroid tumors and cross-validate the results of immunohistochemistry with those of HRPT2 analysis.
We performed parafibromin and cyclin D1 immunostaining and HRPT2 gene analysis using loss of heterozygosity studies and sequencing analysis in parathyroid specimens from 11 patients with carcinoma (eleven primary tumors, one skin, and four lung metastases), 22 with sporadic adenomas, and 4 with atypical adenomas.
Ten out of eleven parathyroid cancers were negative for parafibromin staining and showed HRPT2 gene abnormalities. The remaining sample was negative for immunostaining and genetic analyses. All but one sporadic adenomas showed parafibromin immunoreactivity and no HRPT2 gene abnormalities. The sample with negative immunostaining carried an HRPT2 mutation. Two atypical adenomas were positive and two negative with parafibromin staining. No HRPT2 abnormalities were found in these samples. Cyclin D1 expression was heterogeneous and there was no relationship between expression/expression level of cyclin D1 and parafibromin expression.
We have shown that negative parafibromin staining is almost invariably associated with HRPT2 mutations and confirm that loss of parafibromin staining strongly predicts parathyroid malignancy. In clinical practice, these tests could be particularly useful in the subset of parathyroid tumors with equivocal histological examination. However, their diagnostic value in this setting remains to be proven.
European Journal of Endocrinology 06/2007; 156(5):547-54. · 3.42 Impact Factor
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Filomena Cetani, Elena Pardi,
Elena Ambrogini,
Monica Lemmi,
Simona Borsari,
Luisella Cianferotti,
Edda Vignali,
Paolo Viacava,
Piero Berti,
Stefano Mariotti,
Aldo Pinchera,
Claudio Marcocci
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ABSTRACT: Familial isolated primary hyperparathyroidism (FIPH) can result from either incomplete expression of a syndromic form of familial primary hyperparathyroidism [multiple endocrine neoplasia type 1 (MEN 1), hyperparathyroidism-jaw tumour syndrome (HPT-JT) or familial hypocalciuric hypercalcaemia (FHH)] or still unrecognized causes. Design Genetic analyses of MEN1, HRPT2 and CASR genes in FIHP.
Seven well-characterized Italian kindreds with FIHP, with negative clinical features for MEN 1, HPT-JT and FHH. The mean age (+/- SD) at diagnosis was 45 +/- 17 years (range 18-70 years) in the probands and 42 +/- 18 years (range 15-69 years) in the other affected subjects.
Direct sequencing of germline DNA of the MEN1, HRPT2 and CASR genes from probands. The region of interest was amplified in some family members.
Germline MEN1 mutations were detected in three kindreds. Multiglandular involvement was found in all but one affected subject belonging to the three kindreds with MEN1 mutations. In these patients persistence/relapse of the disease was observed unless an extensive parathyroidectomy (excision of 3(1)/(2) glands) had been performed, with the exception of one patient, who is currently normocalcaemic 168 months after excision of two glands. No mutations of MEN1, HRPT2 and CASR genes were identified in the remaining four families.
MEN1 genotyping appears worthwhile in FIHP families, as the finding of mutation(s) may predict multiglandular involvement and therefore have practical surgical implications, and prompt further investigation in the family, with the possibility of identifying new cases and beginning a programme of periodic surveillance for emergence of tumours in all carriers.
Clinical Endocrinology 03/2006; 64(2):146-52. · 3.17 Impact Factor
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Filomena Cetani, Elena Pardi,
Simona Borsari,
Paolo Viacava,
Giada Dipollina,
Luisella Cianferotti,
Elena Ambrogini,
Elisabetta Gazzerro,
Giacomo Colussi,
Piero Berti,
Paolo Miccoli,
Aldo Pinchera,
Claudio Marcocci
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ABSTRACT: We investigated the involvement of the HRPT2 gene by loss of heterozygosity analysis and direct sequencing in a kindred with hyperparathyroidism-jaw tumor syndrome (HPT-JT) and three kindreds with familial isolated primary hyperparathyroidism (FIHP). Seven patients with sporadic parathyroid cancers and 35 with parathyroid adenomas with no family history of primary hyperparathyroidism or HPT-JT were also studied. A germline heterozygous substitution G to A was found in the donor splice site of intron 1 in one of the three FIHP families. No mutations were identified in the HPT-JT kindred. A somatic HRPT2 mutation was found in four of seven patients with parathyroid cancers, two of which were unreported frameshift mutations (195insT and 195insA) in exon 2. Consistent with recent findings, two of seven patients with sporadic parathyroid cancer had germline mutations. Four adenomas showed loss of heterozygosity at HRPT2, whereas a somatic HRPT2 mutation was found in one. In conclusion, we provide additional evidence for a strong association between HRPT2 gene mutations and sporadic parathyroid cancer. The finding that two of the seven patients with sporadic parathyroid cancer carried an HRPT2 germline mutation suggests that they might have occult HPT-JT. Our results also confirm the need for testing HRPT2 gene in FIHP families.
Journal of Clinical Endocrinology & Metabolism 12/2004; 89(11):5583-91. · 6.50 Impact Factor
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Filomena Cetani, Elena Pardi,
Paolo Viacava,
Giada Di Pollina,
Giovanni Fanelli,
Antonella Picone,
Simona Borsari,
Elisabetta Gazzerro,
Paolo Miccoli,
Piero Berti,
Aldo Pinchera,
Claudio Marcocci
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ABSTRACT: Some histological features may suggest the malignant nature of a parathyroid tumour. However, the diagnosis of parathyroid cancer can only be definitively established in the presence of local invasion or metastases.
We further investigated the role of the retinoblastoma gene (Rb1) and the breast cancer susceptibility gene (BRCA2) in the differential diagnosis between benign and malignant parathyroid tumours by evaluating loss of heterozygosity (LOH) at these loci and Rb protein (pRb) immunohistochemistry.
Fifty-three parathyroid adenomas from patients with sporadic primary hyperparathyroidism (PHPT) and 10 parathyroid cancer specimens were studied. Microsatellite polymorphisms at the Rb1 and BRCA2 loci were polymerase chain reaction (PCR) amplified from each patient's paired tumour and leucocyte DNA samples, using oligonucleotide primers flanking the repeat sequence. Immunohistochemical staining of pRb was carried out using a monoclonal antibody.
All but one of the 53 tumour-leucocyte pairs was informative for at least one of the three polymorphic markers of the Rb1 gene. Fifteen adenomas (28.8%) showed LOH. Regarding the BRCA2 gene, 46 tumour-leucocyte pairs were informative and LOH was present in eight (17.4%). All six carcinomas had LOH for at least one marker at the Rb1 locus. LOH for the BRCA2 microsatellite was found in three of the five informative primary tumour samples. Immunohistochemical analysis revealed that all adenomas were positive and the number of pRb-positive cells varied significantly among different samples. The mean percentage of stained cells was 15.7%. Eleven of the 30 (36.7%) adenomas showed sparse positive staining, 13 (43.3%) intermediate staining and six (20%) extensive staining. All parathyroid cancers were entirely negative for pRb immunostaining.
Inactivation of the Rb1 gene is a common event in parathyroid tumorigenesis. Retention of heterozygosity seems to exclude parathyroid malignancy, which is suggested by the combined finding of LOH and lack of protein expression.
Clinical Endocrinology 02/2004; 60(1):99-106. · 3.17 Impact Factor
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ABSTRACT: We describe a 45-yr-old woman with metastatic breast cancer and hypercalcemia previously diagnosed as hypercalcemia of malignancy and treated with bisphosphonates without changes of serum calcium (s-Ca). At the time of our evaluation, biochemical data [s-Ca, 10.8 mg/dl (2.70 mmol/liter); PTH, 24.4 pg/ml (2.6 pmol/liter); 24-h urinary calcium, 160 mg (4.0 mmol); calcium/creatinine clearance, 0.007] suggested the diagnosis of familial hypocalciuric hypercalcemia. Three of five relatives had mild hypercalcemia [s-Ca, 10.7-11.2 mg/dl (2.67-2.80 mmol/liter)] and detectable serum PTH [24.5-29.0 pg/ml (2.6-3.1 pmol/liter)]. A novel heterozygous I212T missense mutation in exon 4 of the calcium-sensing receptor (CaR) gene was found in the proband and affected relatives but not in unaffected relatives. Expression of the mutant I212T CaR in COS-7 cells resulted in no response of inositol phosphates to any calcium concentration. The calcium dose-response curve of the coexpressed receptors [wild-type/I212T] suggested that the mutant receptor interferes with the function of the wild-type receptor. In conclusion, we describe a case of familial hypocalciuric hypercalcemia due to a novel CaR mutation, in a woman with breast cancer in whom hypercalcemia was initially attributed to hypercalcemia of malignancy.
Journal of Clinical Endocrinology & Metabolism 12/2003; 88(11):5132-6. · 6.50 Impact Factor
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ABSTRACT: Description of two unrelated Italian kindreds with familial hypocalciuric hypercalcaemia (FHH), an autosomal dominant disease mostly caused by heterozygous inactivating mutations of the Ca2+ sensing receptor (CaR).
We studied 11 members of the two families. Genomic DNA was isolated from peripheral blood leucocytes in all family members and in 50 unrelated Italian controls. Total serum and ionized calcium, PTH, creatinine, phosphate, magnesium, and urinary calcium clearance to creatinine clearance ratio were measured. Direct sequencing of the entire coding region of the CaR was performed in the probands. Functional studies were performed in COS-7 cells transiently expressing the mutated CaR.
In the proband of family A direct sequencing revealed a novel heterozygous Y218C missense mutation in exon 4. The same mutation was identified in the affected but not in the unaffected family members or in any of the 50 unrelated Italian controls. Transient expression of the Y218C CaR in COS-7 cells revealed a blunted Ca2+-evoked accumulation of inositol trisphosphates, indicating that the Y218C is a loss-of-function mutation. Cotransfection experiments showed that the mutant receptor had no impact on the function of the wild-type receptor, suggesting that a reduced expression of the normal CaR, rather than a dominant-negative effect, accounted for the functional impairment. In the proband of family B an already described heterozygous P55L missense mutation in exon 2 of the CaR gene was found. The same mutation was identified in the affected family members.
We described two familial hypocalciuric hypercalcaemia kindreds with loss-of-function mutations of the Ca2+ receptor gene and identified a novel heterozygous mutation (Y218C) characterized by a blunted response to Ca2+ stimulation compared to the wild-type receptor and no interference with the function of the wild-type Ca2+ receptor.
Clinical Endocrinology 03/2003; 58(2):199-206. · 3.17 Impact Factor
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Filomena Cetani, Elena Pardi,
Anna Giovannetti,
Edda Vignali,
Simona Borsari,
Franco Golia,
Luisella Cianferotti,
Paolo Viacava,
Paolo Miccoli,
Maurizio Gasperi,
Aldo Pinchera,
Claudio Marcocci
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ABSTRACT: SummaryOBJECTIVES Familial hyperparathyroidism may occur as part of hereditary syndromes, including multiple endocrine neoplasia types 1 and 2 (MEN1 and MEN2A), hyperparathyroidism-jaw tumour (HPT-JT) syndrome and familial isolated hyperparathyroidism (FIHP). It is unclear whether the latter is a distinct genetic entity or a variant of MEN1 or HPT-JT, where, because of reduced penetrance, only primary hyperparathyroidism (PHPT) is present. In the present study, we describe two unrelated Italian kindreds with FIHP, in which the clinical, histopathological and genetic analyses of the MEN1 gene and HPRT2 locus at 1q21-32 suggest that both might be a variant of MEN1 and HPT-JT syndromes.PATIENTS AND DESIGN We studied 16 members, aged 14–50 years, of two unrelated kindreds with FIHP. Genomic DNA was isolated from peripheral blood leucocytes in all family members, and from parathyroid tissue in those who underwent parathyroidectomy.MEASUREMENTS Ionized calcium and PTH were measured in all family members. The nine coding exons and 16 splice junctions of the MEN1 gene from constitutional DNA were amplified by the polymerase chain reaction (PCR) and sequenced. Parathyroid glands were obtained from five subjects. Allelic deletions (loss of heterozygosity, LOH) of chromosomes 11q13 and 1q21-q32 were assessed using PYGM and D11S449, and D1S215, D1S222, D1S428, D1S412, D1S413 and D1S477, respectively. Forward primers were conjugated with 5′ fluorescent dye. PCR products were analysed using an ABI PRISM 310 sequencer.RESULTS Five members of family 1 and three of family 2 had PHPT. A heterozygous deletion of 1 bp of the MEN1 gene in exon 10 (1785delA) was found in affected members of family 1. No MEN1 gene mutation was found in any member of family 2. LOH at 11q13 was observed in family 1 tumours, but not in those from family 2. Studies at 1q21-32 showed LOH in two family 2 tumours, whereas a retained heterozygosity was found in the remaining member. No LOH at 1q21-32 was found in family 1 tumours. The pathology of family 1 showed chief cell hyperplasia with a diffuse-nodular pattern of growth. Cut surface showed no cystic structures. Typical parathyroid adenoma was diagnosed in one member of family 2 and atypical adenoma in the remaining two. These tumours showed cystic structures.CONCLUSIONS In conclusion, we describe two unrelated kindreds with FIHP which, on the basis of histopathological and genetic studies, could be labelled as variants of the MEN1 and HPT-JT syndromes, respectively. Therefore, an extensive analysis of the genes involved in these diseases should be performed in families with familial isolated hyperparathyroidism to identify the subset linked to the MEN1 gene or to the HPRT2 locus.
Clinical Endocrinology 05/2002; 56(4):457 - 464. · 3.17 Impact Factor
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Filomena Cetani, Elena Pardi,
Anna Giovannetti,
Edda Vignali,
Simona Borsari,
Franco Golia,
Luisella Cianferotti,
Paolo Viacava,
Paolo Miccoli,
Maurizio Gasperi,
Aldo Pinchera,
Claudio Marcocci
[show abstract]
[hide abstract]
ABSTRACT: Familial hyperparathyroidism may occur as part of hereditary syndromes, including multiple endocrine neoplasia types 1 and 2 (MEN1 and MEN2A), hyperparathyroidism-jaw tumour (HPT-JT) syndrome and familial isolated hyperparathyroidism (FIHP). It is unclear whether the latter is a distinct genetic entity or a variant of MEN1 or HPT-JT, where, because of reduced penetrance, only primary hyperparathyroidism (PHPT) is present. In the present study, we describe two unrelated Italian kindreds with FIHP, in which the clinical, histopathological and genetic analyses of the MEN1 gene and HPRT2 locus at 1q21-32 suggest that both might be a variant of MEN1 and HPT-JT syndromes.
We studied 16 members, aged 14-50 years, of two unrelated kindreds with FIHP. Genomic DNA was isolated from peripheral blood leucocytes in all family members, and from parathyroid tissue in those who underwent parathyroidectomy.
Ionized calcium and PTH were measured in all family members. The nine coding exons and 16 splice junctions of the MEN1 gene from constitutional DNA were amplified by the polymerase chain reaction (PCR) and sequenced. Parathyroid glands were obtained from five subjects. Allelic deletions (loss of heterozygosity, LOH) of chromosomes 11q13 and 1q21-q32 were assessed using PYGM and D11S449, and D1S215, D1S222, D1S428, D1S412, D1S413 and D1S477, respectively. Forward primers were conjugated with 5' fluorescent dye. PCR products were analysed using an ABI PRISM 310 sequencer.
Five members of family 1 and three of family 2 had PHPT. A heterozygous deletion of 1 bp of the MEN1 gene in exon 10 (1785delA) was found in affected members of family 1. No MEN1 gene mutation was found in any member of family 2. LOH at 11q13 was observed in family 1 tumours, but not in those from family 2. Studies at 1q21-32 showed LOH in two family 2 tumours, whereas a retained heterozygosity was found in the remaining member. No LOH at 1q21-32 was found in family 1 tumours. The pathology of family 1 showed chief cell hyperplasia with a diffuse-nodular pattern of growth. Cut surface showed no cystic structures. Typical parathyroid adenoma was diagnosed in one member of family 2 and atypical adenoma in the remaining two. These tumours showed cystic structures.
In conclusion, we describe two unrelated kindreds with FIHP which, on the basis of histopathological and genetic studies, could be labelled as variants of the MEN1 and HPT-JT syndromes, respectively. Therefore, an extensive analysis of the genes involved in these diseases should be performed in families with familial isolated hyperparathyroidism to identify the subset linked to the MEN1 gene or to the HPRT2 locus.
Clinical Endocrinology 05/2002; 56(4):457-64. · 3.17 Impact Factor
