[Autosomal recessive chorea-acanthocytosis linked to 9q21].

A 34-year-old male, son of consanguineous parents, had a progressive neurological illness characterized by seizures, tics, choreic movements and mood changes. Acanthocytosis was present in blood. The level of creatine kinase was elevated. Normobetalipoproteinemia was noted. No KX group changes of McLeod syndrome were found. Serial neuroimaging studies demonstrated progressive caudate atrophy. Muscular biopsy confirmed the existence of non-specific myopathy. Genetic study demonstrated homozigosity for the 9q21 region.