Idiopathic hypercalciuria: A familial generalized renal hyperexcretory state

Idiopathic hypercalciuria: A familial generalized renal hyperexcretory state. Twenty-two children with idiopathic hypercalciuria (IH) as well as their parents and siblings were compared to 29 control children and their parents and siblings. Urinary calcium excretion following calcium deprivation or calcium loading was significantly higher in parents and siblings of the IH children than in the corresponding controls. Significantly higher rates of glomerular filtration and increased urinary excretion of sodium potassium and phosphate were found in all family members in the IH group as compared to controls. Significant positive correlations of the five variables studied (glomerular filtration and urinary excretion of calcium, phosphate, sodium, and potassium) were noted within individuals and also within families, both in the IH and the control groups, notwithstanding the lower mean levels in the latter. Serum concentrations of calcium, phosphate, potassium, and sodium were similar in the IH and controls. The distributions of all urinary variables in both the IH and control groups were unimodal with considerable overlap of the two groups, suggesting that IH may be a single entity, possibly representing the upper end of normality. Our data seem to indicate that IH is more likely to be due to nutritional than to genetic factors, since maintenance of sodium potassium homeostatis in the face of increased excretion necessitates increased ingestion of these electrolytes, while increased sodium ingestion is known to be associated with increased urinary excretion of calcium, potassium, and phosphate. Hypercalciurie idiopathique: Un etat d'hyperexcretion renale generalisee familiale. Vingt-deux enfants avec une hypercalciurie idiopathique (IH) ainsi que leurs parents et fratrie ont ete compares a 29 enfants controles et leurs parents et fratrie. L'excretion urinaire de calcium apres restriction calcique ou charge calcique etait significativement plus elevee chez les parents et la fratrie des enfants IH que chez les controles correspondants. Des debits de filtration glomerulaire significativement plus eleves, et des elevations de l'excretion urinaire de sodium, de potassium, et de phosphate ont ete trouves chez tous les membres des familles du groupe IH par rapport au controle. Des correlations positives significatives des cinq variables etudiees (filtration glomerulaire et excretion urinaire de calcium, phosphate, sodium, et potassium) ont ete notees chez les individus, et aussi dans les familles chez les groupes IH et controle, malgre des concentrations moyennes plus faibles chez le dernier. Les concentrations seriques de calcium, phosphate, potassium, et sodium etaient identiques chez les IH et les controles. Les distributions de toutes les variables urinaires chez les groupes IH et controles etaient unimodales, avec un chevauchement considerable entre les deux groupes, suggerant que l'IH pourrait etre une entite unique, representant peut-etre la partie superieure de la normale. Nos donnees semblent indiquer que l'IH est probablement due a des facteurs plus nutritionnels que genetiques, puisque le maintien de l'homeostasie du sodium et du potassium en presence d'une augmentation de l'excretion necessite l'augmentation de l'ingestion de ces electrolytes, tandis que l'augmentation accrue de sodium est connue pour etre associee avec l'augmentation de l'excretion urinaire de calcium, de potassium, et de phosphate.