Large C9orf72 repeat expansions are not a common cause of Parkinson's disease

The concept of a pathological overlap between neurodegenerative disorders is gaining momentum. We sought to determine the contribution of C9orf72 repeat expansions, recently discovered as a cause of frontotemporal dementia and amyotrophic lateral sclerosis, in a large number of Parkinson's disease patients. No large expansions were identified in our cohort. (C) 2012 Published by Elsevier Inc.