ERYTHROCYTE ANION TRANSPORTER AND ANTIBRAIN IMMUNOREACTIVITY IN CHOREA-ACANTHOCYTOSIS - A CONTRIBUTION TO ETIOLOGY, GENETICS, AND DIAGNOSIS

Novel structural and functional alterations in the erythrocyte anion t ransporter band 3 are described in one patient with definite, and in t wo patients with symptoms compatible with chorea-acanthocytosis, but w ithout acanthocytes. Immunoblotting analysis shows increased fragmenta tion of band 3, and sulfate flux measurements indicate that anion tran sport activity is reduced in the erythrocytes of these patients. These changes are similar, but not identical to those observed during norma l erythrocyte aging. In addition, distinct antibrain immunoreactivity was present in the plasma of these patients. A family study indicates that abnormal erythrocyte band 3 structure and function and antibrain immunoreactivity may be phenotypes of two independent, genetically det ermined factors, that are part of the heterogenic defect of chorea-aca nthocytosis. The findings in the patients without acanthocytes indicat e that the biochemical abnormalities may be related to a chorea-acanth ocytosis-like, amyotrophic extrapyramidal movement disorder with axona l neuropathy. Measurement of erythrocyte sulfate transport and plasma antibrain immunoreactivity could be of use in establishing the diagnos is and further unravelling the genetic background of chorea-acanthocyt osis and related syndromes.