Аннотация:Erythrocytes of healthy volunteers and of patients with hereditary chorea were studied. Evaluation of the state of cellular membrane was carried out by measuring osmotic resistance, activity of Na+, K(+)-ATPase and protein composition. In the patients osmotic resistance of erythrocytes was distinctly decreased down to 66.3 +/- 3.3, while the Na+, K(+)-ATPase activity was increased 4-fold as compared with controls. Protein composition of erythrocyte membranes, studied by means of two-dimensional electrophoresis, was similar both in healthy persons and in patients with hereditary chorea when the electrophoretograms were analyzed visually. An additional protein with Mr = 30,000 and r-1-0.25 was detected in one of the patients. Slowly sedimenting fraction of erythrocytes was found in almost all the patients with hereditary chorea when erythrocytes aging was studied by means of fractionation in Ficoll density gradient. The fraction was not observed in healthy persons. These data suggest that the cell membranes in Huntington's chorea are altered as compared with normal state.