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)

Idiopathic low-molecular-weight (LMW) proteinuria is a newly described renal disease in Japan and Italy. We report on 7 patients who manifested bilateral or unilateral nephrocalcinosis, as demonstrated by abdominal computed tomography scans. Renal histology revealed calcinosis of renal tubules in 2 patients. Computed tomography is a reliable method for the detection of nephrocalcinosis in this disorder. Hypercalciuria was also seen in 6 patients. A calcium-loading test performed in 2 patients suggested that hypercalciuria was of renal origin. Although the true pathogenesis is still not known, hypercalciuria and nephrocalcinosis appear to be a common complication in patients with idiopathic LMW proteinuria. These complications and clinical features suggest that idiopathic LMW proteinuria in Japan is likely to be identical to Dent's disease in the United Kingdom.
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PMID:Hypercalciuria and nephrocalcinosis in patients with idiopathic low-molecular-weight proteinuria in Japan: is the disease identical to Dent's disease in United Kingdom? 775 56

An 8-year-old boy presented with precocious puberty and hypertension. He had hypokalemia, increased serum aldosterone and testosterone levels and low plasma renin activity. An adrenal adenoma was found using imaging methods and was removed. Postoperatively aldosterone, testosterone and blood pressure returned to normal. Renal ultrasonography findings were consistent with nephrocalcinosis, which might be explained by long lasting hypokalemic metabolic alkalosis and hypercalciuria. Precocious pseudopuberty progressed into true puberty due to the maturational effect of testosterone. Nephrocalcinosis was still present 8 years later and hypertension was recurring obviously as a consequence of increased peripheral resistance.
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PMID:Aldosterone and testosterone producing adrenal adenoma in childhood. 775 88

In 1991, we reported that hypercalciuria is a common finding in our pediatric patient population with osteogenesis imperfecta (OI) (17 of 47 = 36%). Here, we prospectively screened 12 of these hypercalciuric children, on average 4 years subsequent to the discovery of elevated urine calcium levels, for adverse effects on renal function. Despite an ad libitum decrease since initial investigation of about 30% in their previously normal dietary calcium intake (adjusted for body weight), 8 of the 12 patients remained hypercalciuric (urine calcium/creatinine > 0.62 mmol/mmol). We found, once again, that urinary calcium levels significantly correlated with the severity of the skeletal disease as assessed by z-score for height (r = -0.75, p = 0.005). Evaluation of kidney function, however, revealed: (i) normal routine urinalysis in all but 1 subject who had transient microscopic hematuria; (ii) unremarkable concentrating ability determined by fasting urine osmolality; (iii) normal creatinine clearance, and (iv) unremarkable ultrasonography to measure renal size and to screen for nephrocalcinosis or nephrolithiasis. Although no significant renal compromise was detected with these studies in our hypercalciuric pediatric OI patients, investigation of affected adults, especially those severely affected, will be important to assess whether this is a long-term problem and if adverse effects on the kidneys do develop.
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PMID:Hypercalciuria in osteogenesis imperfecta: a follow-up study to assess renal effects. 778 36

The oculocerebrorenal (Lowe) syndrome is an X-linked recessive disorder characterized by congenital cataracts, hypotonia, developmental delay, poor growth and renal tubular dysfunction. Although the disorder has been mapped to chromosome Xq24-26, the underlying metabolic defect remains unknown. The renal component of the Lowe syndrome comprises tubular dysfunction, that is tubular proteinuria and generalized aminoaciduria progressing to the renal Fanconi syndrome, with later glomerular disease. Clinical problems typically include polyuria, acidosis, hypophosphatemia with rickets and eventually end stage renal disease. Hypercalciuria and its sequelae (nephrocalcinosis and nephrolithiasis) have not been described as cardinal features of the untreated disorder although they reportedly complicate vitamin D and calcium therapy of rickets. We discuss 5 boys with congenital cataracts, hypotonia, developmental delay, failure to thrive and the renal Fanconi syndrome who were diagnosed with the Lowe syndrome and in whom hypercalciuria was documented at diagnosis. We conclude that hypercalciuria and its sequelae may occur commonly in patients with the Lowe syndrome as a component of tubular dysfunction or a complication of therapy.
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PMID:Hypercalciuria and nephrocalcinosis in the oculocerebrorenal syndrome. 786 19

We report a male newborn with typical clinical signs of idiopathic infantile hypercalcemia (IIH); that is, hypercalcemia, hypercalciuria, an elfin face and nephrocalcinosis without giving Vitamin D3 supplementation to the patient. He had been treated with a vitamin D-free, low calcium milk and rectal administration of exogenous calcitonin (elcatonin). The latter seemed to be more effective as a treatment for IIH. The serum calcium level came within the normal range and the serum 1,25-dihydroxyvitamin D3 (1,25[OH]2D3) level decreased from 101.5 to 75.6 pg/mL with the treatments mentioned above. These results suggest that a high serum concentration of 1,25(OH)2D3 is part of the pathogenesis of IIH. However, we were not able to clarify the pathogenesis of the high serum concentration of 1,25(OH)2D3.
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PMID:Idiopathic infantile hypercalcemia discovered in the newborn period. 787 92

Dent's disease, an X-linked renal tubular disorder, is a form of Fanconi syndrome which is characterized by proteinuria, hypercalciuria, nephrocalcinosis, kidney stones and renal failure. Previous studies localised the gene responsible to Xp11.22, within a microdeletion involving the hypervariable locus DXS255. Further analysis using new probes which flank this locus indicate that the deletion is less than 515 kb. A 185 kb YAC containing DXS255 was used to screen a cDNA library from adult kidney in order to isolate coding sequences falling within the deleted region which may be implicated in the disease aetiology. We identified two clones which are evolutionarily conserved, and detect a 9.5 kb transcript which is expressed predominantly in the kidney. Sequence analysis of 780 bp of ORF from the clones suggests that the identified gene, termed hCIC-K2, encodes a new member of the CIC family of voltage-gated chloride channels. Genomic fragments detected by the cDNA clones are completely absent in patients who have an associated microdeletion. On the basis of the expression pattern, proposed function and deletion mapping, hCIC-K2 is a strong candidate for Dent's disease.
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PMID:Isolation and partial characterization of a chloride channel gene which is expressed in kidney and is a candidate for Dent's disease (an X-linked hereditary nephrolithiasis). 787 26

We describe a familial form of renal Fanconi syndrome characterized by hypercalciuria, low-molecular-weight proteinuria, nephrocalcinosis and slowly progressive renal failure. Males are much more severely affected than females. The patients studied included 15 males and 10 females, and five families with up to three generations involved. Studies of the two largest families described here have already shown that their disease is inherited on the X-chromosome. The series contains the two unrelated patients originally described by Dent and Friedman in 1964 as 'hypercalcuric rickets'.
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PMID:Dent's disease; a familial proximal renal tubular syndrome with low-molecular-weight proteinuria, hypercalciuria, nephrocalcinosis, metabolic bone disease, progressive renal failure and a marked male predominance. 792 1

A distal acidification defect is frequently observed in the syndrome of familial hypomagnesaemia-hypercalciuria and hence this condition can be confused with primary distal renal tubular acidosis (RTA). This study demonstrates that in four unrelated patients with familial hypomagnesaemia-hypercalciuria the acidification defect is functionally different from that present in primary distal RTA. All patients exhibited hypomagnesaemia, hypermagnesuria, hypercalciuria, hyposthenuria, nephrocalcinosis and slight reduction of glomerular filtration rate (GFR). A moderate degree of metabolic acidosis was also present and basal data showed an inappropriately high urine pH (5.7-5.9) and a positive urine anion gap (Na + K-Cl = 11-28 mmol/l). Stimulation of distal acidification induced a fall in urine pH (4.7-5.6), but ammonium excretion remained low despite factoring by GFR (26-46 mumol/min per 1.73 m2, 35-54 mumol/100 ml GF). The urine to blood PCO2 gradient also remained low after sodium bicarbonate loading (1.3-17.7 mmHg). These results are best explained by both defective ammonia transfer to the deep nephron and impaired hydrogen ion secretion at the level of the medullary collecting duct, and probably are secondary effects of the medullary interstitial nephropathy.
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PMID:Pathophysiology of the renal acidification defect present in the syndrome of familial hypomagnesaemia-hypercalciuria. 794 33

Vitamin D and its metabolites are well-established regulators of bone mineral homeostasis. Their clearest role is in the prevention and treatment of rickets and osteomalacia, bone diseases characterized by inadequate bone formation, and mineralization. Much of the effectiveness of vitamin D and its active metabolite 1,25(OH)2D in treating such disorders rests with their ability to increase serum levels of calcium and phosphate principally by stimulating intestinal calcium and phosphate absorption. Osteoporosis is not a disease resulting from obvious deficiencies in vitamin D, calcium, and phosphate. More subtle deficiencies, however, may be found, especially among the elderly with decreased intake of dairy products, reduced sunlight exposure, and less efficient intestinal absorption of bone minerals. Such subtle deficiencies may account for the ability of vitamin D and calcium supplementation to have a beneficial effect on bone mineral density in this population. Estrogen administration to postmenopausal females raises 1,25(OH)2D levels, presumably through increased renal production, and this increase is associated with increased intestinal calcium transport. Serum measurements of the vitamin D metabolites in general, however, and 1,25(OH)2D in particular do not consistently show evidence of a decrease at the time of menopause. Although most studies show a fall in intestinal calcium transport with age, which can be reversed with 1,25(OH)2D or estrogen, even these observations have not been found consistently. Thus, some investigators have addressed the issue of tissue resistance to 1,25(OH)2D and have noted decreased VDR in the intestine and reduced 1,25(OH)2D accumulation by bone with age. Despite no obvious deficiency of vitamin D in most patients with osteoporosis, clinical trials with vitamin D or 1,25(OH)2D show promise. Vitamin D treatment will probably prove most efficacious in populations with marginal vitamin D intake and/or limited sunlight exposure; high doses would not be required, and the treatment would be safe. This would be a physiologic and not a pharmacologic use of vitamin D. The use of 1,25(OH)2D for treatment of osteoporosis in individuals with adequate nutrition and sunlight exposure may require somewhat higher than physiologic doses to be effective. Perhaps such doses are necessary to stimulate osteoblast activity and/or differentiation; by raising the serum calcium level, such doses of 1,25(OH)2D might block its otherwise stimulatory effect on osteoclast number and activity. Such doses run the risk of hypercalcemia and hypercalciuria, leading to nephrolithiasis and/or nephrocalcinosis. These undesirable side effects appear to be less common with the use of 1 alpha OHD compared with 1,25(OH)2D, but this may be because of the lower levels of calcium consumption in Japan where 1 alpha OHD is widely prescribed.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Role of vitamin D, its metabolites, and analogs in the management of osteoporosis. 798 88

We studied 25 patients treated with oral phosphate and 1,25(OH)2 vitamin D for 0.5-15 y (mean, 7 y) to determine the incidence of nephrocalcinosis and its relationship to treatment, renal function, and growth. During the follow-up period, 3 hypercalcaemic and 13 random hypercalciuric episodes were documented. Creatinine clearances and urine concentration tests were normal in all patients. One patient's 24-h urine specimen indicated hypercalciuria. Kidney ultrasonography revealed nephrocalcinosis in 80% of the patients, but its severity was not significantly related to the dose of calcitriol or of phosphate, the duration of treatment, the age at which treatment was started, or growth. None of the 9 untreated affected family members had nephrocalcinosis. Longitudinal studies revealed that the greatest loss in height velocity occurred during the first 2 y of life. Our study shows that nephrocalcinosis is a common complication of phosphate and 1,25(OH)2D3 treatment, but it is not necessarily associated with impaired renal function. Although the treatment failed to prevent a decrease in height velocity during infancy, it effectively maintained height velocity after 2 y of age.
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PMID:Nephrocalcinosis in X-linked hypophosphataemic rickets: its relationship to treatment, kidney function, and growth. 800 49


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