title: Familial hypomagnesemia-hypercalciuria in 2 siblings.
abstract: Familial hypomagnesemia-hypercalciuria with nephrocalcinosis and renal insufficiency in childhood is a rarely described disease. Two siblings of consanguineous Tunesian parents (first cousins), a 2-year-old boy and a 4-year-old girl presented with renal insufficiency and severe bilateral nephrocalcinosis. Both were found to have decreased serum and intracellular magnesium concentrations, increased urinary excretion of magnesium and calcium, mild glomerular and severe tubular proteinuria and low citrate excretion in urine. Pathological biochemical findings and the severity of nephrocalcinosis of the boy compared to findings of the sister were strongly marked, Histology of the boy's kidney showed severe medullary nephrocalcinosis, tubular atrophy, focal lymphoplasmacellulary infiltration, focal cortical fibrosis, immature glomerula, segmental and global glomerulosclerosis. Subsequent mutation analysis revealed a homozygous frameshift mutation in the gene paracellin-1 in both affected individuals. Therapy consisted of sodium bicarbonate, cholecalciferol, calcitriol, hydrochlorothiazide, citrate salts and oral magnesium administration. Hypercalciuria decreased in both children by therapy with thiazide diuretics, but hypomagnesemia was unresponsive to magnesium administration. After a 32-month follow-up the boy commenced hemodialysis at the age of 5 years, whereas his sister showed no decline in renal function.
authors.affiliation: Department of Pediatrics, University Children's Hospital, University of Münster, Germany.
authors.forename: E
authors.initials: E
authors.lastname: Kuwertz-Bröking
authors.forename: S
authors.initials: S
authors.lastname: Fründ
authors.forename: M
authors.initials: M
authors.lastname: Bulla
authors.forename: R
authors.initials: R
authors.lastname: Kleta
authors.forename: C
authors.initials: C
authors.lastname: August
authors.forename: K
authors.initials: K
authors.lastname: Kisters
mesh_terms: D002118:Calcium / Q000097:blood / Q000652:urine*; D002675:Child, Preschool; D057167:Claudins; D003241:Consanguinity; D005260:Female; D016368:Frameshift Mutation; D006801:Humans; D008275:Magnesium Deficiency / Q000235:genetics*; D008297:Male; D008565:Membrane Proteins / Q000235:genetics*; D009397:Nephrocalcinosis / Q000150:complications / Q000235:genetics* / Q000473:pathology; D010375:Pedigree; D051437:Renal Insufficiency / Q000209:etiology / Q000473:pathology
chemical_list: D057167:Claudins; D008565:Membrane Proteins; C502010:claudin 16; D002118:Calcium