Abstracts from the Fourth International Symposium on Neuroacanthocytosis
July 1-2, 2008
London and Oxford
Chairs: Prof. Kailash Bhatia, MD, FRCP, Institute of Neurology, University College London; Prof. Anthony P. Monaco, MD, PhD, Wellcome Trust Centre for Human Genetics, University of Oxford
Organizers: Antonio Velayos-Baeza, PhD; Susanne Schneider, MD; Glenn Irvine
1-7 Caudate nucleus pathology and obsessive-compulsive disorder in Chorea-Acanthocytosis
Neuropsychiatry Unit, Royal Melbourne Hospital, Melbourne, Australia
Chorea-acanthocytosis (ChAc) is an exceptionally rare autosomal recessive disorder (1 in 5 million) associated with seizures, chorea and peripheral blood acanthocytes. Patients often have dramatic caudate atrophy noted on magnetic resonance imaging. Notably, the disorder presents with adolescent or adult-onset obsessive-compulsive disorder (OCD) in up to 25% of individuals, implicating dysfunction of the caudate nucleus and its relay function in the lateral orbito-frontal loop (LOFL). MRI scans from a number of clinicians in Europe, Australia and the Americas were collected (n=14), and then age- and gender-matched against controls (n=14) and patients with Huntington's disease (HD, n=14). Caudate nuclei were traced using an established protocol; caudate volume corrected for intracranial volume was determined, and shape analysis was conducted on caudate shape using permutation analysis, following spherical harmonic modeling and parametric mesh generation. HD patients had a 10% reduction in caudate volume (not significant) and only modest shape changes compared to controls; ChAc patients in comparison showed a dramatic 80% reduction in size, a flattening of the caudate and the loss of most of the caudate head. This suggests that dramatic neuronal loss in the caudate results in the loss of its function in inhibiting motor acts, leading to OCD-like illness in a number of ChAc patients.