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Query: UMLS:C0020437 (hypercalcemia)
 10,293 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Primary hyperparathyroidism is characterized by hypercalcemia and elevated parathyroid hormone levels. It can be caused by overactivity of one (adenoma or carcinoma) or more (hyperplasia or multiple adenoma) parathyroid glands. Parathyroid adenoma and hyperplasia are usually mono- or oligoclonal neoplasms. To establish whether parathyroid cancer has a genetic composition distinct from parathyroid adenoma, we analyzed 10 adenoma and 10 carcinoma cases by comparative genomic hybridization (CGH). Results show clear differences between the constitution of adenoma and carcinoma genomic DNA. The most frequent genomic alterations in adenoma included deletions on chromosomes 11, 17 (5 of 10 cases), and 22 (7 of 10 cases). In parathyroid carcinoma, frequent chromosomal deletions were on chromosome arm 1p (4 of 10 cases) and chromosome 17 (3 of 10 cases), and gains were on chromosome 5 (3 of 10 cases). Our data indicate that different genetic changes could contribute to the development of parathyroid adenoma and carcinoma; genomic losses predominate in adenoma, and gains along with some losses are found in carcinoma. Furthermore, the CGH results implicate several chromosomal regions that may harbor genes that could be potentially involved in the development of parathyroid adenoma and carcinoma.
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PMID:Comparative genomic hybridization analysis of human parathyroid tumors. 977 6

Williams syndrome (WS) is a contiguous gene deletion disorder caused by haploinsufficiency of genes at 7q11.23. We have shown that hemizygosity of elastin is responsible for one feature of WS, supravalvular aortic stenosis (SVAS). We have also implicated LIM-kinase 1 hemizygosity as a contributing factor to impaired visual-spatial constructive cognition in WS. However, the common WS deletion region has not been completely characterized, and genes for additional features of WS, including mental retardation, infantile hypercalcemia, and unique personality profile, are yet to be discovered. Here, we present a physical map encompassing 1.5 Mb DNA that is commonly deleted in individuals with WS. Fluorescence in situ hybridization analysis of 200 WS individuals shows that WS individuals have the consistent deletion interval. In addition, we identify three novel genes from the common deletion region: WS-betaTRP, WS-bHLH, and BCL7B. WS-betaTRP has four putative beta-transducin (WD40) repeats, and WS-bHLH is a novel basic helix-loop-helix leucine zipper (bHLHZip) gene. BCL7B belongs to a novel family of highly conserved genes. We describe the expression profile and genomic structure for each of these genes. Hemizygous deletion of one or more of these genes may contribute to developmental defects in WS.
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PMID:Complete physical map of the common deletion region in Williams syndrome and identification and characterization of three novel genes. 986 Mar 2

The E2A-HLF fusion gene, formed by the t(17;19)(q22;p13) chromosomal translocation, is thought to drive the leukemic transformation of early B-cell precursors by repressing an evolutionarily conserved apoptotic pathway. To test this hypothesis, we sought to identify downstream targets of E2A-HLF in t(17;19)+ pro-B leukemia cells (UOC-B1) that had been transfected with a zinc-inducible vector encoding a dominant-negative suppressor (E2A-HLF[dn]) of the oncoprotein. Representational difference analysis of mRNAs from E2A-HLF(dn)+ UOC-B1 cells grown with (E2A-HLF inactive) or without (E2A-HLF active) the addition of zinc yielded several differentially expressed cDNA fragments that were individually subcloned. Two of the clones, designated F-5 and G-4, hybridized with mRNAs that were upregulated by E2A-HLF. Levels of both transcripts declined sharply within 8 to 12 hours after suppression of E2A-HLF DNA-binding activity, becoming undetectable after 96 hours. The F-5 cDNA was identified as a portion of ANNEXIN VIII, whose product was expressed in promyelocytic leukemia cells and UOC-B1 cells, but not in other leukemic cell lines. A novel full-length cDNA cloned with the G-4 fragment encoded a protein that we have named SRPUL (sushi-repeat protein upregulated in leukemia). It is normally expressed in heart, ovary, and placenta, but could not be detected in leukemic cell lines other than UOC-B1. Neither protein prevented apoptosis in interleukin-3-dependent murine pro-B cells, suggesting that they have paraneoplastic roles in leukemias that express E2A-HLF, perhaps in the disseminated intravascular coagulopathy and hypercalcemia that characterize these cases.
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PMID:Two candidate downstream target genes for E2A-HLF. 986 77

Calcium homeostasis by the kidneys and parathyroids is mediated by the calcium-sensing receptor (CaSR), which is located on 3q21-q24 and belongs to family C of the superfamily of G-protein coupled receptors that includes those for metabotropic glutamate, certain pheromones, and gamma-amino butyric acid (GABA-B). Inactivating CaSR mutations result in familial benign hypercalcemia (FBH), or familial hypocalciuric hypercalcemia (FHH), whereas activating mutations result in hypocalcemic hypercalciuria. However, not all FBH patients have CaSR mutations, which, together with the mapping of another FBH locus to 19p13.3, suggests that additional CaSRs or second messengers may be involved. These may be identified by positional cloning, and we therefore performed a genomewide search, using chromosome-specific sets of microsatellite polymorphisms, in an Oklahoma family with an FBH variant (FBHOk), for which linkage to 3q and 19p had been excluded. Linkage was established between FBHOk and eight chromosome 19q13 loci, with the highest LOD score, 6.67 (recombination fraction.00), obtained with D19S606. Recombinants further mapped FBHOk to a <12-cM interval flanked by D19S908 and D19S866. The calmodulin III gene is located within this interval, and DNA sequence analysis of the coding region, the 5' UTR, and part of the promoter region in an individual affected with FBHOk did not detect any abnormalities, thereby indicating that this gene is unlikely to be implicated in the etiology of FBHOk. This mapping of FBHOk to chromosome 19q13 will facilitate the identification of another CaSR or a mediator of calcium homeostasis.
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PMID:Localization of familial benign hypercalcemia, Oklahoma variant (FBHOk), to chromosome 19q13. 991 58

Autosomal dominant hypocalcemia (ADH), caused by activating mutations of the calcium-sensing receptor (CaSR), is characterized by hypocalcemia with an inappropriately low concentration of PTH. Among 11 missense mutations of CaSR reported to date in patients with ADH or sporadic hypocalcemia, functional properties of 8 mutant CaSRs were characterized. Here, we describe a novel mutation of CaSR and its functional property in a family with ADH. The 41-yr-old male proband had asymptomatic hypocalcemia with a history of recurrent nephrolithiasis. His father had asymptomatic hypocalcemia, but his mother was normocalcemic. PCR-single strand conformation polymorphism and sequencing revealed that both the proband and the father had a novel heterozygous mutation in CaSR gene that causes lysine to asparagine substitution at codon 47 (K47N), which is in the extracellular domain of CaSR, like 6 of 11 known activating mutations. Using HEK293 cells transfected with wild-type or K47N CaSR complementary DNA, the intracellular Ca2+ concentration was assessed in response to changes in the extracellular Ca2+ concentration. The EC50 of the mutant CaSR for the extracellular Ca2+ concentration was 2.2 mmol/L and was significantly lower than that of wild-type (3.7 mmol/L). These results confirm that this mutation is responsible for ADH in this family. The fact that several inactivating mutations in familial hypocalciuric hypercalcemia occur in amino acid around K47 suggests the importance of the N-terminal portion of the receptor in extracellular Ca sensing.
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PMID:A novel activating mutation in calcium-sensing receptor gene associated with a family of autosomal dominant hypocalcemia. 992 Jan 8

Inactivating mutations in the calcium-sensing receptor (CaSR) cause familial hypocalciuric hypercalcaemia (FHH) and neonatal severe hyperparathyroidism (NSHPT). Earlier investigations showed patients with FHH are heterozygous, and NSHPT are homozygous for inactivating mutations. However, one adult patient with severe hypercalcaemia and hypocalciuria has been reported to have a homozygous inactivating mutation in CaSR (Pro39Ala). This suggested that mutant CaSR in this patient had some residual activity and hypercalcaemia was not so severe as to be fatal. However, the function of this mutant CaSR was not evaluated. In the present study, we describe a novel homozygous mutation in an adult patient with severe hypercalcaemia and hypocalciuria, and evaluate the function of the mutant CaSRs. The DNA sequence of CaSR gene was determined by direct sequencing of the polymerase chain reaction product. The function of mutant CaSR was analysed by creating mutant cDNAs by in vitro mutagenesis, transfection of mutant cDNAs into HEK293 cells and measuring intracellular ionized Ca in response to changes in extracellular Ca. A 26-year-old Japanese woman showed marked hypercalcaemia with an elevated parathyroid hormone (PTH) level. Her consanguineous parents had asymptomatic hypercalcaemia with relative hypocalciuria. The proband had a homozygous mutation at codon 27 of CaSR gene (CAA-->CGA, Gln27Arg). Her parents were heterozygous for this mutation. EC50 for Ca of this mutant CaSR (GIn27Arg) was 4.9 mM. EC50 of another mutant CaSR (Pro39Ala) whose homozygous mutation was discovered in an adult patient was 4.4 mM. These EC50s were significantly higher than that of wild-type CaSR (3.7} 0.1 mM), but were the lowest among the reported EC50s for inactivating mutations of CaSR. These results indicate that serum Ca and PTH levels are determined by residual function of mutant CaSR in patients with homozygous mutation in CaSR, and that patients having homozygous mutant CaSRs with mild dysfunction do not suffer from fatal hypercalcaemia in infancy and can survive into adulthood.
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PMID:An adult patient with severe hypercalcaemia and hypocalciuria due to a novel homozygous inactivating mutation of calcium-sensing receptor. 1046 15

Two heterozygous PTH/PTH-related peptide (PTHrP) receptor missense mutations were previously identified in patients with Jansen's metaphyseal chondrodysplasia (JMC), a rare form of short limb dwarfism associated with hypercalcemia and normal or undetectable levels of PTH and PTHrP. Both mutations, H223R and T410P, resulted in constitutive activation of the cAMP signaling pathway and provided a plausible explanation for the abnormalities in skeletal development and mineral ion homeostasis. In the present study we analyzed genomic DNA from four additional sporadic cases with JMC to search for novel activating mutations in the PTH/PTHrP receptor, to determine the frequency of the two previously identified missense mutations, H223R and T410P, and to determine whether different mutations present with different severity of the disease. The H223R mutation was identified in three novel JMC patients and is, therefore, to date the most frequent cause of JMC. In the fourth patient, a novel heterozygous missense mutation was found that changes isoleucine 458 in the receptor's seventh membrane-spanning region to arginine (I458R). In COS-7 cells expressing the human PTH/PTHrP receptor with the I458R mutation, basal cAMP accumulation was approximately 8 times higher than that in cells expressing the wild-type receptor despite impaired surface expression of the mutant receptor. Furthermore, the I458R mutant showed higher responsiveness to PTH than the wild-type receptor in its ability to activate both downstream effectors, adenylyl cyclase and phospholipase C. Like the H223R and the T410P mutants, the I458R mutant had no detectable effect on basal inositol phosphate accumulation. Overall, the patient with the I458R mutation exhibited clinical and biochemical abnormalities similar to those in patients with the previously identified H223R and T410P mutations.
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PMID:A novel parathyroid hormone (PTH)/PTH-related peptide receptor mutation in Jansen's metaphyseal chondrodysplasia. 1048 64

1alpha,25-dihydroxyvitamin D(3) and two synthetic analogs, 1alpha, 25-dihydroxy-16-ene-23-yne-vitamin D(3) (Ro 23-7553) and 1alpha, 25-dihydroxy-16-ene-24-oxo-vitamin D(3) (JK-1624-3), were tested for their ability to specifically inhibit growth and promote differentiation of human colon cancer cells in comparison with a series of 1beta-(hydroxymethyl) congeners of the natural hormone, such as 1beta-(hydroxymethyl)-3alpha,25(OH)(2)-16-ene,24-oxo-vitamin D(3) (JK-1624-2), 1beta-(hydroxymethyl)-3alpha, 25-dihydroxy-16-ene-26,27-dihomo vitamin D(3) (JK-1626-2), and 1beta-(hydroxymethyl)-3alpha,25-dihydroxy-22,24-diene-26,27- dihomo vitamin D(3) (MCW-EE). Western blot analysis revealed that reduction of cyclin D1 levels is a key mechanism by which the vitamin D compounds under investigation inhibit Caco-2 tumor cell growth. Both the 1alpha-hydroxy- as well as the 1beta-hydroxymethyl-type vitamin D compounds, which exhibit only low affinity for the vitamin D receptor, significantly reduced [(3)H]thymidine DNA labeling in confluent Caco-2 cell cultures. This suggests that high-affinity binding to the vitamin D receptor is not an absolute prerequisite for genomic action on tumor cell growth. Hybrid analogs JK-1624-2 and MCW-EE, although antimitotically active, were rather ineffective in promoting phenotypic differentiation of human colon cancer cells. However, because both compounds also do not promote osteoclast differentiation from hematopoetic bone marrow cells, they still could be used as antimitotic agents in cancer therapy, even at dose levels that, with other analogs, could cause hypercalcemia.
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PMID:Biological effects of 1alpha-hydroxy- and 1beta-(hydroxymethyl)-vitamin D compounds relevant for potential colorectal cancer therapy. 1052 58

A 69-year-old man had a hepatic tumour occupying the left and half of the right lobe, with portal vein thrombus. There were hypercalcaemia and hypophosphataemia with increased nephrogenous cyclic adenosine monophosphate; bone metastases were excluded. Serum parathyroid hormone-related protein (PTHrP) was elevated, but no increase in intact parathyroid hormone (PTH) or vitamin D3 metabolites was found. At autopsy the histological features were typical of sclerosing hepatic carcinoma. By immunohistochemistry PTHrP was detected in cancer cell nests but not in the fibrous stroma. PTHrP transcripts were demonstrated by in situ hybridization using a polymerase chain reaction (PCR)-derived single-stranded DNA probe. Tumour cells expressed AE1 and CA19-9 (markers for cholangioepithelium) and CEA (for bile canaliculi). Electron microscopy revealed microvilli on the apical surface, and secretory granules 100 nm in diameter were observed. These findings indicate that this case is one of cholangiocellular sclerosing hepatic carcinoma. The interaction between cancer and stromal cells may be the cause of PTHrP overexpression.
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PMID:In situ demonstration of parathyroid hormone-related protein mRNA in sclerosing hepatic carcinoma. 1059 13

We report three boys with adrenal hypoplasia congenita (AHC) and additional findings that represent a new syndrome, IMAGe: Intrauterine growth retardation, Metaphyseal dysplasia, AHC, and Genital anomalies. Each presented shortly after birth with growth retardation and severe adrenal insufficiency. Each of the three patients had mild dysmorphic features, bilateral cryptorchidism, a small penis, and hypogonadotropic hypogonadism. Skeletal surveys revealed metaphyseal dysplasia in all three and epiphyseal dysplasia in two. The patients had documented or suspected hypercalciuria and/or hypercalcemia, resulting in nephrocalcinosis in one and in prenatal liver and spleen calcifications in another. AHC presents most often either as an isolated abnormality, caused by mutations in the DAX1 gene, or as part of an Xp21 contiguous gene syndrome, caused by a deletion of the Duchenne muscular dystrophy, glycerol kinase, and DAX1 genes. All three patients with the IMAGe association had normal creatine kinase levels and no evidence of glycerol kinase deficiency. Sequence analysis of DNA from these patients revealed no mutation in the DAX1- or steroidogenic factor-1-coding sequences, nor was a deletion of DAX1 detected. Identification of the molecular basis of the IMAGe association will give new insight into the pathogenesis of this syndromic relationship involving bone, adrenal cortical, and pituitary development.
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PMID:IMAGe, a new clinical association of intrauterine growth retardation, metaphyseal dysplasia, adrenal hypoplasia congenita, and genital anomalies. 1059 84


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