Multiple system atrophy is not caused by C9orf72 hexanucleotide repeat expansions

Abstract

Multiple system atrophy (MSA) is a fatal neurodegenerative disorder of unknown etiology that presents with variable combinations of progressive ataxia, parkinsonism, and autonomic instability. Pathologic expansion of a hexanucleotide repeat in the C9orf72 gene has been demonstrated to cause neurodegeneration with diverse neurologic presentations. To test the hypothesis whether pathologic expansions in C9orf72 are a cause of MSA, we undertook genetic screening in 100 neuropathologically confirmed cases. No pathologic repeat expansions were detected suggesting that MSA is not a C9orf72-related neurodegenerative disease.