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)

A hitherto undescribed association of sensorineural hearing loss and Fanconi syndrome (FS) is reported in a 10 year old black male. The patient presented with growth failure developing at the age of 6 and rachitic changes were detected the following year. No known cause for FS was identified, and renal biopsy was within normal limits. Distal tubular acidification and the threshold for proximal tubular bicarbonate reabsorption were normal, as was urine concentrating capacity. He was found to have significant hypercalciuria (urine calcium excretion 10 mg/kg/day) despite dietary calcium restriction, and urine calcium excretion increased further following an oral calcium load. Dietary sodium restriction to 16 mEq/kg/day resulted in a fall in urine calcium loss, which remained elevated at 6 mg/kg/day. Serum parathyroid hormone and 1,25 dihydroxy vitamin D3 (1,25(OH)2D3) concentrations were in the normal range. Treatment with neutral phosphate dietary supplementation resulted in partial healing of rickets and normal growth rate. Hypercalciuria resolved during phosphate administration (urine calcium excretion 3 mg/kg/day) without a fall in urine sodium excretion. It is concluded that in this patient with FS, hyperphosphaturia resulted in phosphate depletion and secondary hypercalciuria. A similar mechanism of hypercalciuria may be operative in a variety of renal tubular disorders affecting children and adults.
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PMID:Hypercalciuria in a child with primary Fanconi syndrome and hearing loss. 685 42

IMAGe syndrome is a rare condition, first reported by Vilain et al., in 1999, characterized by intrauterine growth restriction, metaphyseal dysplasia, congenital adrenal hypoplasia, and genital anomalies. Patients with this condition may present shortly after birth with severe adrenal insufficiency, which can be life-threatening if not recognized early and commenced on steroid replacement therapy. Other reported features in this condition include, hypercalciuria and/or hypercalcemia, craniosynostosis, cleft palate, and scoliosis. We report on a 7-year-old boy with IMAGe syndrome, who in addition to the features in the acronym also has bilateral sensorineural hearing loss which has not been reported in previously published cases of IMAGe syndrome. We discuss the clinical presentation in our patient and review the literature in this rare multisystem disorder.
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PMID:IMAGe syndrome: Case report with a previously unreported feature and review of published literature. 2110 98

We try to explain why hypercalciuria is absent at diagnosis in some children with an ATP6V1B1 mutation. A 5-month-old girl presented with distal renal tubular acidosis (dRTA) and sensorineural hearing loss. Direct sequencing of the ATP6V1B1 genes disclosed a new homozygous mutation (452 delT) in exon 13. In particular, an absence of hypercalciuria and a normal level of parathyroid hormones were noted. After alkaline therapy, the signs of nephrocalcinosis improved on ultrasound during follow-up. After a review of the literature regarding patients with ATP6V1B1 gene mutations, a young age seemed to be an important factor for normocalciuria. The probable mechanism of normocalciuria and a dynamic mode of calcium excretion in patients with dRTA is proposed. The determinant factors include the degree of systemic acidosis, urine pH, genetic polymorphisms, age, dietary factors, and volume status. Low sodium intake may be a major determinant of normocalciuria in these patients. It is suggested that hypercalciuria is usually absent at diagnosis of dRTA in young infants. Blood pH, plasma bicarbonate concentration, urinary citrate levels, and growth catch-up may be better indicators of adequate alkali therapy in normocalciuric children. Volume contraction, low salt content in infant formula, and alkaline urine in young infants are likely to account for the increased calcium reabsorption.
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PMID:Why is hypercalciuria absent at diagnosis in some children with ATP6V1B1 mutation? 2161 96

Distal renal tubular acidosis (DRTA) is characterized by tubular defects in urinary acidification and hyperchloremic metabolic acidosis, hypokalemia, hypercalciuria, hypocitraturia, nephrocalcinosis and nephrolithiasis. Mutations in ATP6V1B1 cause DRTA associated with sensorineural hearing loss. The objective of this multicenter study is to screen DRTA patients with sensorineural hearing loss for ATP6V1B1 gene mutations and present genotype/phenotype correlation. Clinical data in five unrelated consanguineous families with DRTA and hearing loss were obtained in Turkey. For mutation screening, all coding exons of ATP6V1B1 were PCR-amplified and sequenced from genomic DNA. In our cohort of five families, there were four different homozygous ATP6V1B1 mutations in affected individuals: c.91C>T (p.R31X), c.232G>A (p.G78R), c.497delC (p.T166RfsX9) and c.1155dupC (p.I386HfsX56). Our study shows that rare and family-specific variants in ATP6V1B1 are responsible for DRTA and sensorineural hearing loss syndrome in Turkey. While firm genotype-phenotype correlations are not available, detailed clinical and molecular analyses provide data to be used in genetic counseling.
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PMID:ATP6V1B1 mutations in distal renal tubular acidosis and sensorineural hearing loss: clinical and genetic spectrum of five families. 2392 81