Clinical and pathological features of amyotrophic lateral sclerosis caused by mutation in the C9ORF72 gene on chromosome 9p.
Two studies recently identified a GGGGCC hexanucleotide repeat expansion in a non-coding region of the chromosome 9 open-reading frame 72 gene (C9ORF72) as the cause of chromosome 9p-linked amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD). In a cohort of 231 probands with ALS, we identified the C9ORF72 mutation in 17 familial (27.4%) and six sporadic (3.6%) cases. Patients with the mutation presented with typical motor features of ALS, although subjects with the C9ORF72 mutation had more frequent bulbar onset, compared to those without this mutation. Dementia was significantly more common in ALS patients and families with the C9ORF72 mutation and was usually early-onset FTD. There was striking clinical heterogeneity among the members of individual families with the mutation. The associated neuropathology was a combination of ALS with TDP-ir inclusions and FTLD-TDP. In addition to TDP-43-immunoreactive pathology, a consistent and specific feature of cases with the C9ORF72 mutation was the presence of ubiquitin-positive, TDP-43-negative inclusions in a variety of neuroanatomical regions, such as the cerebellar cortex. These findings support the C9ORF72 mutation as an important newly recognized cause of ALS, provide a more detailed characterization of the associated clinical and pathological features and further demonstrate the clinical and molecular overlap between ALS and FTD.
Division of Neurology, University of British Columbia, Vancouver, BC, Canada.
Heather
H
Stewart
Nicola J
NJ
Rutherford
Hannah
H
Briemberg
Charles
C
Krieger
Neil
N
Cashman
Marife
M
Fabros
Matt
M
Baker
Alice
A
Fok
Mariely
M
DeJesus-Hernandez
Andrew
A
Eisen
Rosa
R
Rademakers
Ian R A
IR
Mackenzie
D000690:Amyotrophic Lateral Sclerosis / Q000235:genetics* / Q000378:metabolism / Q000473:pathology; D001921:Brain / Q000378:metabolism / Q000473:pathology*; D000073885:C9orf72 Protein; D002899:Chromosomes, Human, Pair 9; D004268:DNA-Binding Proteins / Q000378:metabolism; D057180:Frontotemporal Dementia / Q000235:genetics* / Q000378:metabolism / Q000473:pathology; D006801:Humans; D009154:Mutation; D011506:Proteins / Q000235:genetics* / Q000378:metabolism; D013116:Spinal Cord / Q000378:metabolism / Q000473:pathology*
D000073885:C9orf72 Protein; C568651:C9orf72 protein, human; D004268:DNA-Binding Proteins; D011506:Proteins