Increased erythrocyte content of Ca2+ in patients with Tarui's disease

To establish by flow cytometry and fluorophores an increased calcium ion load in erythrocytes of four patients with Tarui's disease.

Calcium ion levels were determined in erythrocytes of patients and controls under normal and energy-deprived conditions. Adenylates were measured to assess energy status of incubated erythrocytes.

The experiments were carried out at the Department of Clinical Chemistry of the University Hospital of Uppsala, Sweden.

Four family members with Tarui's disease participated in the study. The proband (patient 1) was a 39-year-old male; patients (male, aged 46 years) 2 and 3 (female, 30 years) were his two siblings. Patient 4 (male, 16 years) was the son of patient 2.

None.

Calcium ion homeostasis was measured under basic conditions and under energy-deprived conditions and related to cellular adenylate content.

All patients showed enhanced erythrocyte calcium ion loading compared to controls under energy-deprived conditions. Under normal conditions, however, three out of the four patients showed an increased erythrocyte calcium ion level compared to controls.

We conclude that erythrocytes from patients with Tarui's disease have an increased Ca2+ permeability, initiating compensatory mechanisms involving increased Ca2+ pump activity and increased glycolytic flux, which are not always sufficient to keep erythrocyte calcium ion concentration within physiological range.