Mutation analysis of C9orf72 in patients with corticobasal syndrome

Corticobasal syndrome (CBS) is a neurodegenerative disease characterized by progressive asymmetrical rigidity and apraxia, cortical sensory loss, myoclonus, dystonia, and cognitive impairment. CBS is usually sporadic and associated with tau pathology but there are reports of TDP-43 pathology. We screened 39 CBS cases to determine if any of the cases could be explained by a G4C2-repeat expansion in a noncoding region of C9orf72 gene, the most common genetic cause of frontotemporal lobar degeneration and amyotrophic lateral sclerosis. One patient with CBS had a large (>50 repeats) expansion in C9orf72. Our case features a 63-year-old right-handed woman who developed mild apathy 9 years before presentation, which progressed to include behavioral symptoms, oral stereotypies, significant language impairment, parkinsonism and apraxia. A magnetic resonance imaging acquired at age 60 years, that is, 6 years after disease onset revealed significant asymmetric left > right frontotemporal atrophy, including orbitofrontal and parietal areas. Her father developed a behavioral syndrome and died at an early age. This case highlights the importance of genetic screening for C9orf72 in patients with CBS.