Chorea-acanthocytosis (ChAc, Online Mendelian Inheritance in Man [OMIM] 200150; http://www.ncbi.nlm.nih.gov/Omim/ provided in the public domain by the National Center for Biotechnology Information, Bethesda, MD) is an autosomal recessive neurodegenerative disorder that belongs to the group of neuroacanthocytosis (NA) syndromes.
1 These diseases combine neurologic abnormalities with an unusual spiky appearance (acanthocytosis) of the red blood cells. Other disorders in this group include aβ-lipoproteinemia (OMIM 200100), hypo-β-lipoproteinemia (OMIM 107730), and McLeod syndrome (OMIM 314850).
1 Unlike those diseases, the level of serum β-lipoprotein in ChAc is normal, as is the expression of the red blood cell antigen Kell, which is reduced in McLeod syndrome.
1 Mutations in the chorein gene (vacuolar protein sorting 13A [
VPS13A], on chromosome 9q, region 21) are responsible for ChAc.
2 3 ChAc is an uncommon disease that has been reported under different names (Levine-Critchley syndrome, familial neuroacanthocytosis, or just neuroacanthocytosis).
4 5 6 7 8 9 Its prevalence is unknown, and only approximately 300 cases have become known so far worldwide. The disease presents at 25 to 45 years of age with choreatic movements similar to Huntington’s disease and has a progressive course.
1 4 8 Orofacial dyskinesia causes dysarthria, dysphagia, motor and vocal tics, and lip and tongue biting. Cognitive and behavioral changes, seizures, parkinsonism, peripheral neuropathy, and myopathy are common. Neuroimaging and autopsy studies reveal degeneration of the basal ganglia, including the caudate nuclei, putamen, and globus pallidus
1 5 8 9 10 ; but, unlike Huntington’s disease, the cerebral cortex is usually spared.
8 Laboratory testing typically reveals acanthocytosis in 5% to 50% of the red blood cells and increased serum concentrations of muscle enzymes.