Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0020438 (hypercalciuria)
 2,502 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

It is now evident that the term Bartter syndrome does not represent a unique entity but encompasses a variety of disorders of renal electrolyte transport. Application of molecular biology techniques has permitted a better understanding of these "Bartter-like syndromes," which at present can be divided into three different genetic and clinical entities. Neonatal Bartter syndrome is observed in newborn infants and characterized by polyhydramnios, premature delivery, life-threatening episodes of fever and dehydration during the early weeks of life, growth retardation, hypercalciuria, and early-onset nephrocalcinosis. Two molecular defects have been identified: either at the gene encoding the renal bumetanide-sensitive Na-K-2Cl cotransporter (NKCC2) or the gene encoding an ATP-sensitive inwardly rectifying K channel (ROMK). "Classic" Bartter syndrome is mostly observed during infancy and childhood and is characterized clinically by polyuria and growth retardation. Nephrocalcinosis is not present. Very recently, either deletions or mutations at the gene encoding a renal chloride channel (ClC-Kb) have been identified. Gitelman syndrome is observed in older children and adults presenting with intermittent episodes of muscle weakness and tetany, hypokalemia, and hypomagnesemia. Mutations at the gene encoding the thiazide-sensitive Na-Cl cotransporter have been identified in the majority of patients studied. Obviously the validity of this classification must be confirmed in the near future when all mutations have been described and genotypic-phenotypic correlations are better defined.
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PMID:Bartter and related syndromes: the puzzle is almost solved. 965 65

Recurrent urinary tract infection (UTI) has not been widely recognized as a clinical manifestation of hypercalciuria in children. We studied 59 children with two or more episodes of UTI, a normal urinary tract, and with hypercalciuria. Clinical manifestations were fever, dysuria, straining with micturition, hematuria, polyuria, abdominal pain, and failure to thrive. Urinary calcium/creatinine ratio was 0.36+/-0.15 mg/mg. Renal function studies included serum bicarbonate (21+/-3 mmol/l), urinary/blood PCO2 difference (11+/-11 mmHg), urinary net acid excretion (63+/-3 micromol/min per 1.73 m2), uric acid fractional excretion (13%+/-12%), and maximal urinary osmolality (920+/-236 mosmol/kg). Treatment included promotion of fluid intake, avoiding excessive salt and protein, and keeping dietary calcium between 900 and 1,200 mg/day. Potassium citrate or hydrochlorothiazide were indicated if hypercalciuria persisted. With this treatment, in 95% of the children, no further episodes of UTI occurred once normocalciuria was achieved. It is possible that hypercalciuria may play a predisposing role for recurrent UTI in children by promoting the formation of microcrystals which damage the uroepithelium. We advocate the investigation of urinary calcium excretion in children with recurrent UTI and a normal urinary tract.
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PMID:Hypercalciuria and recurrent urinary tract infection in Venezuelan children. 1041 65

The neonatal form of Bartter syndrome is characterized by intrauterine onset of polyuria leading to severe polyhydramnios. We report a patient with the early onset of the syndrome and a similar history in a previous sibling who died in early neonatal life. The patient is a female product of 33 weeks of gestation complicated by severe polyhydramnios. Her birth weight was 2,100 g. Polyuria led to severe dehydration on the 3rd day of life. Laboratory studies showed hypokalemia, hyponatremia, and elevated plasma levels of renin and aldosterone. Hypercalciuria was associated with echographic evidence of nephrocalcinosis. Indomethacin therapy resulted in a significant reduction in urine volume and correction of biochemical abnormalities. Growth and development are satisfactory after 4 years of indomethacin therapy, but nephrocalcinosis remains unchanged.
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PMID:Bartter syndrome in a neonate: early treatment with indomethacin. 1068 65

We have used homologous recombination to disrupt the mouse gene coding for the NaK2Cl cotransporter (NKCC2) expressed in kidney epithelial cells of the thick ascending limb and macula densa. This gene is one of several that when mutated causes Bartter's syndrome in humans, a syndrome characterized by severe polyuria and electrolyte imbalance. Homozygous NKCC2-/- pups were born in expected numbers and appeared normal. However, by day 1 they showed signs of extracellular volume depletion (hematocrit 51%; wild type 37%). They subsequently failed to thrive. By day 7, they were small and markedly dehydrated and exhibited renal insufficiency, high plasma potassium, metabolic acidosis, hydronephrosis of varying severity, and high plasma renin concentrations. None survived to weaning. Treatment of -/- pups with indomethacin from day 1 prevented growth retardation and 10% treated for 3 weeks survived, although as adults they exhibited severe polyuria (10 ml/day), extreme hydronephrosis, low plasma potassium, high blood pH, hypercalciuria, and proteinuria. Wild-type mice treated with furosemide, an inhibitor of NaK2Cl cotransporters, have a phenotype similar to the indomethacin-rescued -/- adults except that hydronephrosis was mild. The polyuria, hypercalciuria, and proteinuria of the -/- adults and furosemide-treated wild-type mice were unresponsive to inhibitors of the renin angiotensin system, vasopressin, and further indomethacin. Thus absence of NKCC2 in the mouse causes polyuria that is not compensated elsewhere in the nephron. The NKCC2 mutant animals should be valuable for uncovering new pathophysiologic and therapeutic aspects of genetic disturbances in water and electrolyte recovery by the kidney.
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PMID:Uncompensated polyuria in a mouse model of Bartter's syndrome. 1077 55

Familiar hypomagnesemia with hypercalciuria and nephrocalcinosis is a rare syndrome belonging to the group of heterogeneous tubular diseases whose common characteristic is renal magnesium wasting. We present a 9 year old boy with polyuria, polydipsia and enuresis. Radiologic and ultrasonographic examinations showed nephrocalcinosis. Hypomagnesemia, normokaliemia, hypermagnesiuria, hypercalciuria, incomplete distal tubular acidosis, hypocitraturia and mild renal failure were found. Treatment with magnesium salts, hydrochlorothiazide, potassium citrate and sodium bicarbonate did not restore magnesium or calcium levels to normal. Renal function and nephrocalcinosis remain stable after 3 year's treatment. In conclusion, we report a new case of this rare syndrome caused by a congenital defect in magnesium reabsorption and discuss the evolution of the illness during 3 years' treatment.
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PMID:[Familial hypomagnesemia with hypercalciuria and nephrocalcinosis]. 1169 17

Familial hypomagnesemia with hypercalciuria and nephrocalcinosis (FHHNC) is an autosomal recessive tubular disorder that is frequently associated with progressive renal failure. The primary defect is related to impaired tubular reabsorption of magnesium and calcium in the thick ascending limb of Henle's loop. Mutations in PCLN-1, which encodes the renal tight junction protein paracellin-1 (claudin-16), were identified as the underlying genetic defects. Comprehensive clinical data and the results of PCLN-1 mutation analysis of 25 FHHNC families with 33 affected individuals are presented. Patients presented mainly with urinary tract infections, polyuria, and hematuria at a median age of 3.5 yr. At the time of diagnosis, the GFR was already decreased to <60 ml/min per 1.73 m(2) for 11 patients. Twelve patients exhibited progression to end-stage renal disease, at a median age of 14.5 yr. Treatment with magnesium salts and thiazides seemed to have no effect on the progression of the disease. Genotype analysis revealed PCLN-1 mutations in all except three mutant alleles (94%). Fifteen different mutations were observed, including eight novel mutations. The accumulation of mutations affecting the first extracellular loop was striking, with 48% of all mutant alleles exhibiting a Leu151Phe exchange. Haplotype analysis strongly suggested a founder effect among patients with FHHNC who originated from Germany or eastern European countries. In 13 of 23 families, hypercalciuria and/or nephrolithiasis were observed in otherwise unaffected family members, indicating a possible role of heterozygous PCLN-1 mutations in yielding hypercalciuric stone-forming conditions.
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PMID:Novel paracellin-1 mutations in 25 families with familial hypomagnesemia with hypercalciuria and nephrocalcinosis. 1151 80

Patients with hyperprostaglandin E syndrome/antenatal Bartter syndrome typically have renal salt wasting, hypercalciuria with nephrocalcinosis, and secondary hyperaldosteronism. Antenatally, these patients have fetal polyuria, leading to polyhydramnios and premature birth. Hyperprostaglandin E syndrome/antenatal Bartter syndrome is accompanied by a pathologically elevated synthesis of prostaglandin E(2), thought to be responsible for aggravation of clinical symptoms such as salt and water loss, vomiting, diarrhea, and failure to thrive. In this study administration of the cyclooxygenase-2 (COX-2) specific inhibitor nimesulide to patients with hyperprostaglandin E syndrome/antenatal Bartter syndrome blocked renal prostaglandin E(2) formation and relieved the key parameters hyperprostaglandinuria, secondary hyperaldosteronism, and hypercalciuria. Partial suppression of serum thromboxane B(2) synthesis resulting from platelet COX-1 activity and complete inhibition of urinary 6-keto-prostaglandin F(1alpha), reflecting endothelial COX-2 activity, indicate preferential inhibition of COX-2 by nimesulide. Amelioration of the clinical symptoms by use of nimesulide indicates that COX-2 may play an important pathogenetic role in hyperprostaglandin E syndrome/antenatal Bartter syndrome. Moreover, on the basis of our data we postulate that COX-2-derived prostaglandin E(2) is an important mediator for stimulation of the renin-angiotensin-aldosterone system in the kidney.
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PMID:Pathogenetic role of cyclooxygenase-2 in hyperprostaglandin E syndrome/antenatal Bartter syndrome: therapeutic use of the cyclooxygenase-2 inhibitor nimesulide. 1167 54

We report clinical data of a female patient with Bartter's syndrome who was initially diagnosed with idiophatic hypercalciuria and, subsequently, with hyperprostaglandin E, syndrome. The patient was born after premature delivery with a history of polyhydramnios. During the first two years of life, in spite of evidence for significant failure to thrive, polyuria and special tendency to dehydration, she had no hypokalemia. The acid-base balance was normal except metabolic acidosis during the first few days after she was born. When hypercalciuria was observed, she was treated with thiazides and a low-salt diet. With such treatment she frequently showed hypokalemic alkalosis. Afterwards, once it was possible to determine the levels of renin and aldosterone and the urinary excretion of PGE2, we suspected the diagnosis. DNA sequencing analysis showed that the patient carried a homozygotic mutation in the KCNJ1 gene, coding for the potassium channel ROMK, which results in the premature termination of the protein. It is the first time that this mutation has been found in Spain. The detection of this mutation confirmed a disease that was initially of uncertain diagnosis.
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PMID:[Neonatal Bartter disease diagnosed with the detection of a mutation of the KCNJ1 gene which codifies the synthesis of the renal ROMK1 potassium channel]. 1179 13

We report on two cases of Bartter's syndrome, together with the review of current literature on the aetiology, development and treatment of Bartter's syndrome. Bartter's syndrome belongs to a group of hypokalaemic renal channelopathies, which are caused by a molecular hereditary disorder of ion channels in renal tubules. These channels are located in the lipid layer of cell membranes where they exist as water channels through which ion transport is performed. Based on the type of genetic disorder and clinical presentation, Bartter's syndrome is classified as neonatal, classical and Gitelman's syndrome. Neonatal form is found in newborns and is characterized by foetal polyuria, premature birth, postnatal episodes of severe dehydration, growth retardation, hypercalciuria and early nephrocalcinosis. It is the result of mutation of a gene responsible for renal tubular Na-K-2Cl cotransport or another gene which controls the ATP-dependant potassium channel (ROMK). Classic form is found in young children with polyuria, hypokalaemia and growth retardation. This type is caused by a defect of a gene for chloride channel (CIC-Kb) in the distal tubule. Gitelman's syndrome is found in late childhood or adolescence. It is caused by mutation in the gene for Na-Cl co-transport in the distal tubule. Children with Gitelman's syndrome occasionally have muscle weakness or tetany, hypokalaemia and hypomagnesaemia. Even though there have been advances in understanding the aetiology and pathogenesis of Bartter's syndrome in the recent years, the possibilities and strategies for its management remained almost the same. Treatment is based on prostaglandin inhibitors, potassium sparing diuretics and substitution therapy.
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PMID:[Bartter's syndrome: new classification, old therapy]. 1179 62

Bartter syndrome, which presents clinically with polyuria, urinary potassium loss, hypokalemia, hypercalciuria, and alkalosis, is an autosomal recessive disorder with mutations in genes encoding the Na-K-2Cl cotransporter, the chloride channel CLC-NKB, and the potassium channel ROMK. Prenatal diagnosis of Bartter syndrome is now possible; however, there are no reports of the placental pathology associated with fetal Bartter syndrome. We present the placental pathologic findings in two siblings with fetal Bartter syndrome. Both pregnancies were complicated by polyhydramnios and preterm delivery. The first pregnancy delivered at 30 weeks, and Bartter syndrome was diagnosed in the perinatal period. The subsequent pregnancy required periodic therapeutic amniocentesis secondary to massive polyhydramnios and delivered at 32 weeks gestation. The suspicion of fetal Bartter syndrome was very high in this second pregnancy, and the infant was confirmed to have Bartter syndrome subsequently. Both placentas were large for gestational age, weighing greater than the 95th percentile. Microscopic examination showed extensive subtrophoblastic basement membrane mineralization (special stains positive for iron and calcium) in the chorionic villi. This striking finding was present in both placentas. Subtrophoblastic mineralization has been described in the literature in placentas of fetuses with abnormalities including anencephaly, trisomy 21, and other congenital abnormalities; however, it has also been described in normal pregnancies. Mechanisms of calcification in the placenta are not well understood, but these striking cases suggest that defects in fetal renal excretion of ions can lead to dystrophic calcification within the placenta, particularly in a subtrophoblastic pattern.
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PMID:Placental pathology in fetal bartter syndrome. 1181 71


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