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Choreaacanthocytosis - VPS13A

VPS13A

Clinical Features

Chorea-acanthocytosis (ChAc) is one of the neuroacanthocytosis syndromes which form a group of disorders characterized by the association of neurological abnormalities and spiculated red blood cells called acanthocytes.

ChAc patients exhibit a neurodegenerative disease which usually manifests with a movement disorder (chorea, less frequent parcinsonism) in the third to fifths decade. Dystonia is common and affects the oral region and the tongue in particular, causing dysarthria and serious dysphagia with resultant weight loss. Habitual tongue and lip biting are characteristic. Progressive cognitive and behavioral changes resemble those in a frontal lobe syndrome. Seizures are observed in almost half of affected individuals and can be the initial manifestation. Myopathy and axonal neuropathy results in progressive distal muscle wasting, weakness, hyporeflexia and CK-elevation. CT and MRI reveal atrophy of the caudate nuclei with dilatation of the anterior horns of the lateral ventricles. Acanthocytes are found in the blood of individuals with ChAc in a high proportion of patients. Western blot analysis on EDTA blood samples reveales absence or marked reduction of chorein (for more information see http://www.euro-hd.net/html/na/submodule).

Chorea-acanthocytosis is an autosomal recessive disorder due to mutations of the VPS13A (vacuolar protein sorting 13, yeast, homolog of, A) gene on chromosome 9q21 encoding chorein, a protein involved in cellular trafficking.

Diagnostic