INHERITANCE OF MINERALOCORTICOID EFFECTOR ABNORMALITIES OF HUMAN MONONUCLEAR LEUCOCYTES IN FAMILIES WITH PSEUDOHYPOALDOSTERONISM

SUMMARY In‐vitro effects of aldosterone on intracellular sodium and potassium concentrations have been described for normal human mononuclear leucocytes (HML). After incubation for 1 h at 37|MoC, intracellular sodium and potassium in HML are significantly higher in the presence of 1.4 nM aldosterone than after incubation without aldosterone. As published earlier, these effects were absent in patients with pseudohypoaldosteronism. In the present paper, the families of seven patients with pseudohypoaldosteronism (index cases) were studied. In the first family, two siblings were affected by the disease and had a reduced number of mineralocorticoid (MC) receptors on HML. Intracellular sodium and potassium in HML from these patients did not show a response to 1.4 nM aldosterone. The parents, who were first cousins, had no history of disease and normal receptor data, but in the mother, the response of HML electrolytes to aldosterone was abnormal. In the second family, the mother of a child with pseudohypoaldosteronism, the mother's sister, and her son, had low numbers of MC receptors. Only the aunt of the index case had an uncertain history of the disease. The MC effector mechanism was abnormal in both children and both mothers studied. In a third family, the effector defect was present only in HML of the father. In three further families the abnormality of the effector mechanism was detected in HML of the patient's mother. These data suggest an autosomal dominant inheritance of pseudohypoaldosteronism with variable expression of the gene. The abnormality of the MC effector mechanism seems to be a more sensitive means than the determination of aldosterone plasma levels and MC receptor studies to identify gene carriers without clinical symptoms.