Our findings indicate that the C9ORF72 mutation is a major cause of familial frontotemporal dementia with TDP-43 pathology, that likely accounts for the majority of families with combined frontotemporal dementia/amyotrophic lateral sclerosis presentation, and further support the concept that frontotemporal dementia and amyotrophic lateral sclerosis represent a clinicopathological spectrum of disease with overlapping molecular pathogenesis.
Hexanucleotide repeat expansions in the C9ORF72 gene have been shown to be responsible for both familial and sporadic frontotemporal dementia/amyotrophic lateral sclerosis.
A hexanucleotide repeat expansion in the chromosome 9 open reading frame 72 gene (C9orf72) was recently identified as the most common genetic cause of frontotemporal dementia/amyotrophic lateral sclerosis.
To describe the clinical features of a Brazilian kindred with C9orf72frontotemporal dementia-amyotrophic lateral sclerosis and compare them with other described families with C9orf72 and frontotemporal dementia-amyotrophic lateral sclerosis-causing mutations.
Patients carrying a C9orf72 repeat expansion leading to frontotemporal dementia and/or amyotrophic lateral sclerosis have highly variable ages at onset of disease, suggesting the presence of modifying factors.
In addition, we investigated a cohort of C9orf72 negative patients (n = 2634) affected by frontotemporal dementia and/or amyotrophic lateral sclerosis; and also found that the AA-genotype of rs9357140 was associated with a later age of onset (adjusted P = 0.007 for recessive model).
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.
SEE SCABER AND TALBOT DOI101093/AWW264 FOR A SCIENTIFIC COMMENTARY ON THIS ARTICLE: A GGGGCC repeat expansion in C9orf72 leads to frontotemporal dementia and/or amyotrophic lateral sclerosis.
An expanded hexanucleotide repeat in C9ORF72 has been identified as the most common genetic cause of amyotrophic lateral sclerosis and/or frontotemporal dementia in many populations, including the Greek.