[A case of chorea-acanthocytosis with dilated cardiomyopathy and myopathy].

We report a patient of chorea-acanthocytosis (CA), presenting with dilated cardiomyopathy and myopathy. The patient, 40-year-old male, was seen in our clinic because of progressive gait disturbance. Neurologically, he had chorea, tic, dystonia, diminished tendon reflexes and mild muscular atrophy and weakness. Serum creatine kinase level was elevated to 5.514 IU/l, MRI study showed atrophy of the putamen and caudate nucleus. Peripheral nerve involvement was confirmed pathologically and electrophysiologically. Acanthocytosis was found after repeated blood examinations. Furthermore, he had dilated cardiomyopathy on echocardiogram and cardiac muscle biopsy, and his muscle biopsy taken from gastrocnemius indicated myopathic changes with fiber necrosis. From these clinical and laboratory data, he was suspected to have McLeod syndrome (McS). However, he had normal expression of Kell antigens, and direct sequence of XK gene from genomic DNA sample showed no mutations. Accordingly, he was diagnosed as having CA. As CA shares the similar clinical and laboratory features with McS except Kell antigens, the evaluation of Kell blood system is crucial for differential diagnosis. As seen in our patient, blood sampling should be repeated for identification of acanthocytosis, because the finding is not always clearly present.