Abnormal red-cell calcium pump in patients with idiopathic hypercalciuria

G. Bianchi, G. Vezzoli, D. Cusi, T. Cova, A. Elli, L. Soldati, G. Tripodi, M. Surian, E. Ottaviano, P. Rigatti, S. Ortolani

Research output: Contribution to journalArticlepeer-review

Abstract

Idiopathic hypercalciuria is a common disorder whose inheritance suggests an enzyme abnormality in calcium transport. We measured calcium-magnesium-ATPase activity in erythrocytes from 38 patients (mean age [± SEM], 40 ± 2.1 years) with idiopathic hypercalciuria (24-hour urinary calcium excretion ≥0.1 per kilogram of body weight) and a history of multiple calcium oxalate kidney stones. As compared with 41 healthy controls, the patients with hypercalciuria had increased erythrocyte-membrane calcium-magnesium-ATPase activity (64.2 ± 2.19 vs. 51.6 ± 1.91 nmol of ATP split per milligram per minute; P <0.01) and increased sodium-potassium pump acitivity (6866 ± 233 vs. 6096 ± 228 μmol of sodium per liter of red cells per hour; P <0.05). No significant difference between the two groups was found in erythrocyte sodium-potassium cotransport, sodium-lithium countertransport, or potassium content. In 66 patients with kidney stones (38 with hypercalciuria and 28 with normal calcium excretion), 24-hour urinary calcium excretion correlated with calcium-magnesium-ATPase activity (r = 0.46, P <0.001). Erythrocyte calcium-magnesium-ATPase activity remained unchanged in eight subjects studied after four months on a low-calcium diet. A study of 30 healthy families found significant correlations between mean values in parents and those in offspring for calcium-magnesium-ATPase (r = 0.68, P <0.001) and urinary calcium excretion (r = 0.45, P <0.02), with no significant correlations between parents with respect to these measures (r = 0.27 and r = 0.08, respectively). We conclude that abnormalities in erythrocyte calcium-magnesium-ATPase activity may represent an inherited defect in calcium transport related to the cause of idopathic hypercalciuria.

Original languageEnglish
Pages (from-to)897-901
Number of pages5
JournalNew England Journal of Medicine
Volume319
Issue number14
Publication statusPublished - 1988

ASJC Scopus subject areas

  • Medicine(all)

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