McLeod syndrome and chorea-acanthocytosis are classified with the so-called 
neuroacanthocytosis group of syndromes. Both lead to progressive basal ganglia 
degeneration and were not easily distinguished in the past. With the discovery 
of their molecular bases, mutations of the X-linked gene XK and autosomal 
recessive mutations of the gene coding for chorein, respectively, the two 
phenotypes can now be differentiated and extend the diagnostic spectrum in 
patients presenting with chorea. The present review compares the two conditions 
and proposes a practical approach to diagnosis and treatment. Better-defined 
disease concepts should eventually replace the umbrella term of 
"neuroacanthocytosis." Animal models are needed to understand the underlying 
mechanisms. A final common pathway is likely for the pathogenesis of these 
conditions and is most probably shared with Huntington's disease.