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Query: UMLS:C0020438 (hypercalciuria)
 2,502 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Autosomal dominant hypocalcaemia with hypercalciuria (ADHH) is an intriguing syndrome, in which activating mutations of the calcium sensing receptor (CaSR) have recently been recognised. We describe a kindred with seven affected individuals across three generations, including patients affected in the first decade of life. Age at diagnosis varied from birth to 50 years. Affected members had hypocalcaemia (1.53-1.85 mmol/l), hypercalciuria, low but detectable parathyroid hormone (PTH) and hypomagnesaemia. Four of seven affected individuals were symptomatic (seizures, abdominal pains and paraesthesias), unrelated to severity of hypocalcaemia. Additional complications include nephrocalcinosis (n = 3) and basal ganglia calcification, identified by CT scanning in all five individuals. Symptomatic individuals were treated with calcium and calcitriol to reduce the risk of hypocalcaemic seizures. DNA sequence analysis, identified a mutation in exon 3, codon 129 (TGC-->TAC) of the CaSR gene of seven affected family members, resulting in loss of a conserved cysteine residue, potentially disrupting CaSR receptor dimerisation. Thus, a novel mutation was identified in this family, who demonstrate variability of ADHH phenotype and also illustrate the complexities of clinical management. Optimal management of ADHH is difficult and we recommend judicious treatment to avoid an increased risk of nephrocalcinosis.
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PMID:A family with autosomal dominant hypocalcaemia with hypercalciuria (ADHH): mutational analysis, phenotypic variability and treatment challenges. 1612 46

The frequency of hypercalciuria is increasing in western countries with an incidence of nephrolithiasis which can reach 13%. Hypercalciuria appears as an alteration of the calcium transport system (kidney, bowel, bone) which is regulated by calcitriol and parathormone. The aim of this review was to screen etiologies of hypercalciuria taking into account recent genetic advances (calcium epithelial channel and calcium sensing receptor). Hypercalciuria may be favored by nutritional causes (diet rich in calcium, sodium, carbohydrates, proteins, poor in phosphates and potassium). It may also be related to an increase in calcium absorption (vitamin D excess, primary hyperparathyroidism, sarcoidosis, lymphoma, estrogens, and certain genetic causes), an increase in osteoresorption (bone metastasis, myeloma, Paget, hyperthyroidism, immobilization, hypercortisolism and corticosteroid therapy), or a decrease of kidney tubular resorption (diuretics, Cacci and Ricci, acromegally, Bartter, familial dominant hypocalcemia, Fanconi, Dent, familial hypomagnesemia-hypercalciuria syndrome, type 1 distal tubular acidosis, pseudohypoaldosteronism, diabetes). If no cause is identified, persistence of hypercalciuria after instituting a correct diet is defined as idiopathic hypercalciuria. Treatment of the cause is essential in secondary hypercalciuria, in addition to diet (low sodium intake, normocalcic diet, hydration), associated with thiazide diuretics and biphosphonates if necessary.
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PMID:[Hypercalciuria]. 1635 16

The calcium-sensing receptor has a key role in calcium homeostasis, it is involved in the regulation of the serum calcium level within minutes via the secretion and action of parathyroid and the excretion of calcium in the kidney in a negative feedback manner. Mutations of the calcium sensing receptor gene leads to inactivating and activating mutations resulting in diseases with hypercalcaemia and hypocalcaemia. The loss of function mutations are associated with familial benign hypocalciuric hypercalcaemia (FHH), an autosomal dominant disease characterised by lifelong mild hypercalcaemia, low urinary calcium excretion, and inappropriate high parathyroid hormone levels, sometimes difficult to distinguish from mild asymptomatic primary hyperparathyroidism. Patients with FHH did not profit from parathyroidectomy, a calcium lowering therapy is not necessary. The gain of function mutations of the calcium-sensing receptor are associated with autosomal dominant hypocalcaemia (ADH), a disease characterised by a generally asymptomatic hypocalcaemia, inappropriately high urinary calcium excretion and normal PTH levels. A therapy to raise the serum calcium concentration has to be done carefully and is only indicated in symptomatic patients, because of enhancement of hypercalciuria with the risk of nephrocalcinosis and nephrolithiasis. Molecular genetic analysis of the calcium sensing receptor gene facilitates the sometimes difficult diagnosis. The development of compounds modulating the calcium sensing receptor function and thereby the section of PTH may become an important role in treatment of diseases of calcium metabolism.
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PMID:The role of the extracellular calcium-sensing receptor in health and disease. 1703 19

Idiopathic hypercalciuria is a defect occurring in 5-10% of the general population and most commonly detected in patients with calcium kidney stones or osteoporosis. Although high-penetrance autosomal dominant inheritance cannot be ruled out, hypercalciuria is probably a polygenic phenomenon. Findings obtained in monogenic disorders characterized by renal calcium stones, and/or hypercalciuria, and/or nephrocalcinosis, have suggested a number of genes as candidate genes in the pathogenesis of idiopathic hypercalciuria, i.e. soluble adenylate cyclase, calcium sensing receptor, vitamin D receptor and 1-alpha hydroxylase, sodium-phosphate co-transporter-2, claudin-16, chloride channel 5, etc. All the genetic findings obtained so far do not support the idea of different types of idiopathic hypercalciuria, i.e. absorptive, renal, and resorptive. On the contrary, they support clinical observations, which suggest idiopathic hypercalciuria as a single disorder characterized by altered calcium transport in the intestine, kidney and bone, due to various different combinations of multiple genetic and dietary players.
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PMID:Hypercalciuria revisited: one or many conditions? 1794 25

Renal stone formation due to hypercalciuria is a relatively common disorder with clear evidence for genetic predisposition, but cryptic phenotypic heterogeneity has hampered identification of candidate genes. The R990G single-nucleotide polymorphism (SNP) of the calcium sensing receptor (CASR) gene has been associated with hypercalciuria in stone formers and shows the appropriate functional phenotype in cell culture. In our preliminary association analysis of a case-control cohort, however, we observed significant Hardy-Weinberg disequilibrium (HWD) for the cases (n= 223), but not controls (n= 676) at the R990G locus, pointing us toward the general disease model incorporating HWD. Because there is an adjacent CASR SNP, A986S, which is in negative linkage disequilibrium with R990G, we extended the general disease model to enable testing of a two-site hypothesis. In our data set, there is no lack of fit (P= .345) for the single-locus model for the R990G genotype, and likelihood ratio testing favors a recessive effect with an eight-fold increase in risk (P < .001) for GG homozygotes, relative to wild-type, based on a population prevalence of 2%. Addition of the A986S genotype provides no additional information either by itself or when included in our two-site model.
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PMID:Heterogeneous disease modeling for Hardy-Weinberg disequilibrium in case-control studies: application to renal stones and calcium-sensing receptor polymorphisms. 1913 42

The calcium sensing receptor (CaSR) and fibroblast growth factor 23 (FGF-23) play central roles in the regulation of calcium and phosphorus metabolism, respectively. CaSR controls parathyroid hormone secretion and renal calcium reabsorption. Inactivating mutations of the CaSR result in conditions characterized by hypercalcemia and hypocalciuria, whereas activating lesions cause hypoparathyroidism and hypercalciuria. Calcimimetics are a group of agonists for the CaSR that have been shown to be powerful agents in the treatment of secondary hyperparathyroidism. FGF-23 acts on the kidney to inhibit the reabsorption of phosphate and the synthesis of 1,25(OH)(2)D. Disorders of increased FGF-23 function are associated with hypophosphatemia, inappropriately low 1,25(OH)(2)D levels, and either rickets or osteomalacia. Conversely, decreased FGF-23 activity results in hyperphosphatemia, increased 1,25(OH)(2)D levels, and abnormal soft-tissue calcification. In chronic kidney disease, increases in FGF-23 are being investigated as markers of disease progression.
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PMID:Emerging topics in pediatric bone and mineral disorders 2008. 1961 58

Nephrolithiasis (NL) has high and increasing prevalence in western countries. Most renal stones contain calcium and/or uric acid and often occur as idiopathic stones, while seldom are caused by genetic disorders. Conversely, cystinuria, xantinuria, 2-8 dihydroxyadeninuria only occur in patients with mutations of corresponding genes. Inherited NL must be suspected in case of early onset, positive family history, severe recurrence rate, associated biochemical disorders, abnormal urinary sediment, renal insufficiency, involvement of other organs or apparatus. Pathophysiology is based on different mechanisms: electrolytic abnormalities, altered tubular transport, acid-base imbalances, cystic renal diseases. Sometimes NL is iatrogenic. Here we review some genetic NL, not only characterized by clinical relevance but also by the scientific interest in view of our better understanding of mechanisms of stone formation. Namely, Dents syndrome, calcium sensing receptor mutations, familial hypopomagnesiemic hypercalciuria (FHHNC), hypophosphatemic rickets (HHRH), renal tubular acidosis (dRTA), primary hyperoxaluria (PH), cystinuria, 2-8 dihydroxyadeninuria (2-8 DHA). We will briefly report on prevalence, genetics, pathophysiology, clinical aspects and treatment. The need for early diagnosis stems from the fact that, for most of these, selective treatment may be highly effective and can prevent progression to ESRD. Lastly, a better knowledge and understanding of genetic NL is a premise to study polymorphisms of candidate genes also in the setting of so-called idiopathic disease.
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PMID:[Genetic approach to nephrolithiasis]. 2647 54

Solute Carrier Family 12 member 1 (SLC12A1) gene encodes the sodium-potassium-chloride co-transporter (NKCC2) at the apical membrane of the thick ascending loop of Henle (TAL). Bartter's syndrome (BS) type I is a rare, autosomal recessive, renal tubular disorder associated with mutation of the SLC12A1 gene. Presenting features include: hypokalemic metabolic alkalosis, hypercalciuria and nephrocalcinosis. The many allelic variants reported present with a spectrum of phenotypes, biochemical abnormalities and clinical severities. However, to date, only two reports have described hyperparathyroidism and hypercalcemia in patients with SLC12A1 gene mutations. We describe 4 patients with 4 novel mutation variants in the SLC12A1 gene (c.735C>G, c.1137del, c.2498-2499del, and c.1833delT) presenting with variable degrees of hyperparathyroidism, hypercalcemia, hypokalemic metabolic alkalosis, nephrocalcinosis, and nephrogenic diabetes insipidus. The link between calcium and parathyroid hormone abnormalities in patients with SLC12A1 mutations is unclear; the cases described suggest an association between primary hyperparathyroidism and loss of function mutation of SLC12A1, which may result in an aberrant threshold of the calcium sensing receptor at the level of the kidney.
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PMID:A novel SLC12A1 gene mutation associated with hyperparathyroidism, hypercalcemia, nephrogenic diabetes insipidus, and nephrocalcinosis in four patients. 2809 94