Lack of C9orf72 Repeat Expansion in Taiwanese Patients with Mixed Neurodegenerative Disorders

Background: The hexanucleotide repeat expansion in intron 1 of the C9orf72 gene is recognized as the most common genetic cause of frontotemporal dementia (FTD). There are overlapping clinical and pathological characteristics between FTD and Parkinsonism syndrome, and some FTD patients may present with Parkinsonism. The aim of this study was to analyze the hexanucleotide repeat numbers of C9orf72 gene in a mixed Taiwanese cohort with FTD, Parkinsonism syndrome, Parkinson’s disease (PD), and Alzheimer’s dementia (AD).