FUS mutations in amyotrophic lateral sclerosis: clinical, pathological, neurophysiological and genetic analysis.
OBJECTIVE
FUS gene mutations were recently identified in familial amyotrophic lateral sclerosis (ALS). The present studies sought to define the clinical, post-mortem and neurophysiological phenotypes in ALS families with FUS mutations and to determine the frequency of FUS mutations in familial and sporadic ALS.


METHODS
FUS was screened for mutations in familial and sporadic ALS cases. Clinical, post-mortem and neurophysiological features of large families with FUS mutations are described.


CONCLUSIONS
FUS mutations were evident in 3.2% (4/124) of familial ALS, representing the second most common gene abnormality to be described in familial ALS after SOD1. No mutations were present in 247 sporadic ALS cases. The clinical presentation in 49 affected patients was consistent with a predominantly lower motor neuron disorder, supported by post-mortem findings. Upper motor neuron involvement varied, with Wallerian degeneration of corticospinal tracts present in one post-mortem case but absent in a second case from the same family. Features of cortical hyperexcitability demonstrated upper motor neuron involvement consistent with other forms of familial and sporadic ALS. One case presented with frontotemporal dementia (FTD) indicating that this may be a rare presenting feature in families with FUS mutation. Ubiquitin-positive cytoplasmic skein-like inclusions were present in lower motor neurons, but in contrast to sporadic ALS, no TDP-43 pathology was evident. Mutation-specific clinical features were identified. Patients with a R521C mutation were significantly more likely to develop disease at a younger age, and dropped-head syndrome was a frequent feature. Reduced disease penetrance was evident among most affected families.
Blair
Ian P
IP
Northcott Neuroscience Laboratory, ANZAC Research Institute, Concord Hospital, Sydney, Australia. iblair@med.usyd.edu.au
Williams
Kelly L
KL
Warraich
Sadaf T
ST
Durnall
Jennifer C
JC
Thoeng
Annora D
AD
Manavis
Jim
J
Blumbergs
Peter C
PC
Vucic
Steve
S
Kiernan
Matthew C
MC
Nicholson
Garth A
GA
D000328:Adult; D000368:Aged; D000690:Amyotrophic Lateral Sclerosis / Q000453:epidemiology / Q000235:genetics / Q000473:pathology; D001921:Brain / Q000473:pathology*; D003072:Cognition Disorders / Q000175:diagnosis* / Q000453:epidemiology*; D004252:DNA Mutational Analysis / Q000379:methods; D004268:DNA-Binding Proteins / Q000235:genetics*; D000072159:Dynactin Complex; D056827:Endosomal Sorting Complexes Required for Transport / Q000235:genetics; D005260:Female; D005820:Genetic Testing; D006801:Humans; D008297:Male; D008869:Microtubule-Associated Proteins / Q000235:genetics; D008875:Middle Aged; D009419:Nerve Tissue Proteins / Q000235:genetics; D009483:Neuropsychological Tests; D017354:Point Mutation / Q000235:genetics*; D012333:RNA, Messenger / Q000235:genetics; D034702:RNA-Binding Protein FUS / Q000235:genetics*; D012259:Ribonuclease, Pancreatic / Q000235:genetics; D012720:Severity of Illness Index; D013482:Superoxide Dismutase / Q000235:genetics; D000072105:Superoxide Dismutase-1; D033921:Vesicular Transport Proteins / Q000235:genetics; D055815:Young Adult
C503812:CHMP2B protein, human; D004268:DNA-Binding Proteins; D000072159:Dynactin Complex; D056827:Endosomal Sorting Complexes Required for Transport; D008869:Microtubule-Associated Proteins; D009419:Nerve Tissue Proteins; D012333:RNA, Messenger; D034702:RNA-Binding Protein FUS; C000606290:SOD1 protein, human; C496748:VAPB protein, human; D033921:Vesicular Transport Proteins; D013482:Superoxide Dismutase; D000072105:Superoxide Dismutase-1; C046366:angiogenin; D012259:Ribonuclease, Pancreatic