The proband, a 42-year-old woman with healthy parents in a consanguineous relationship (first-degree cousins) was 32 years old when the first clinical manifestations appeared. These included frequent falls and abrupt, undulant, asymmetric involuntary movements of the trunk, neck, and upper limbs, associated with compulsive lip and tongue biting. At age 35 years, she began to experience episodes of anxiety and depression. Three years later, there was dysphagia to solid foods, dysarthria, and orofacial dyskinesia, with buccolingual self-mutilation (Figure 1) and consequent weight loss of 12 kg. At age 40 years, she could not walk because of hypotonia of the legs. The dysphagia worsened, and she was able to swallow only liquids and semisolid foods. Multiple pharmacologic approaches, including benzodiazepine, oral nondeposit form of haloperidol, biperiden hydrochloride, trihexyphenidyl hydrochloride, clonazepam, levodopa, fluoxetine hydrochloride, and vitamin B complex therapy, were sequentially initiated in an attempt to control symptoms, but with limited response. Two years later, at age 42 years, she became emaciated, anarthric, and reactive to the environment, performing only simple commands. The lower cranial nerves were patently affected, with lingual atrophy and paralysis. The arms and legs were flaccid, paretic, and hyporeflexic. Given the clinical suspicion of CHAC, several peripheral blood smear (PBS) preparations were analyzed, initially yielding nonsignificant results. However, as a consequence of the fortuitous finding of erythrocyte acanthocytosis in her sister several months later, a new PBS was analyzed, which revealed 40% acanthocytes (Figure 1). Other significant laboratory findings included elevated MB fraction of creatine kinase (395 U/L; reference range, 22-269 U /L) and heterozygous ε3/ε4 genotype of apolipoprotein E. There were no remarkable results for α-tocopherol, cobalamin, ceruloplasmin, and copper concentrations in plasma or for lipoprotein electrophoresis and iron kinetics. Assessment of peripheral nerve conduction velocity revealed a severe polyneuropathic axonal sensorimotor defect. Brain imaging assessment included computed tomography and magnetic resonance imaging, which demonstrated global atrophy, especially of the caudate nuclei (Figure 1). Magnetic resonance spectroscopy of the brain showed no meaningful results.