C9orf72 hexanucleotide repeat expansion analysis in Chinese spastic paraplegia patients.

BACKGROUND Recently, a hexanucleotide repeat expansion in the C9orf72 gene has been identified to cause frontotemporal dementia, amyotrophic lateral sclerosis families and many other neurodegenerative diseases. Owing to the overlapping phenotypes among HSP, frontotemporal dementia and amyotrophic lateral sclerosis we hypothesized that C9orf72 expansions might be a genetic risk factor or modifier of HSP. OBJECTIVES The aim of this study was to find out whether C9orf72 expansions also confer risk to spastic paraplegia (SPG). METHODS We recruited 112 genetically unidentified SPG patients, 68 SPG4 patients and 313 controls in mainland China to determine if hexanucleotide repeat of C9orf72 plays a role in spastic paraplegia. RESULTS No large expansion was detected in all subjects. C9orf72 repeat expansions were not associated with onset of HSP. CONCLUSION Our results support the notion that repeat expansions in C9orf72 may not be associated with HSP in China.