Clinical and neuropathologic variation in neuronal intermediate filament inclusion disease.
BACKGROUND
Recently described neuronal intermediate filament inclusion disease (NIFID) shows considerable clinical heterogeneity.


OBJECTIVE
To assess the spectrum of the clinical and neuropathological features in 10 NIFID cases.


METHODS
Retrospective chart and comprehensive neuropathological review of these NIFID cases was conducted.


RESULTS
The mean age at onset was 40.8 (range 23 to 56) years, mean disease duration was 4.5 (range 2.7 to 13) years, and mean age at death was 45.3 (range 28 to 61) years. The most common presenting symptoms were behavioral and personality changes in 7 of 10 cases and, less often, memory loss, cognitive impairment, language deficits, and motor weakness. Extrapyramidal features were present in 8 of 10 patients. Language impairment, perseveration, executive dysfunction, hyperreflexia, and primitive reflexes were frequent signs, whereas a minority had buccofacial apraxia, supranuclear ophthalmoplegia, upper motor neuron disease (MND), and limb dystonia. Frontotemporal and caudate atrophy were common. Histologic changes were extensive in many cortical areas, deep gray matter, cerebellum, and spinal cord. The hallmark lesions of NIFID were unique neuronal IF inclusions detected most robustly by antibodies to neurofilament triplet proteins and alpha-internexin.


CONCLUSIONS
NIFID is a neuropathologically distinct, clinically heterogeneous variant of frontotemporal dementia (FTD) that may include parkinsonism or MND. Neuronal IF inclusions are the neuropathological signatures of NIFID that distinguish it from all other FTD variants including FTD with MND and FTD tauopathies.
Cairns
N J
NJ
Center for Neurodegenerative Disease Research, Department University of Pennsylvania School of Medicine, Philadelphia, PA, USA. cairnsn@abraxas.wustl.edu
Grossman
M
M
Arnold
S E
SE
Burn
D J
DJ
Jaros
E
E
Perry
R H
RH
Duyckaerts
C
C
Stankoff
B
B
Pillon
B
B
Skullerud
K
K
Cruz-Sanchez
F F
FF
Bigio
E H
EH
Mackenzie
I R A
IR
Gearing
M
M
Juncos
J L
JL
Glass
J D
JD
Yokoo
H
H
Nakazato
Y
Y
Mosaheb
S
S
Thorpe
J R
JR
Uryu
K
K
Lee
V M-Y
VM
Trojanowski
J Q
JQ
D000328:Adult; D017668:Age of Onset; D001921:Brain / Q000378:metabolism / Q000473:pathology* / Q000503:physiopathology; D002352:Carrier Proteins / Q000235:genetics / Q000378:metabolism; D003704:Dementia / Q000145:classification* / Q000473:pathology* / Q000503:physiopathology; D003937:Diagnosis, Differential; D018450:Disease Progression; D017809:Fatal Outcome; D005260:Female; D005625:Frontal Lobe / Q000378:metabolism / Q000473:pathology / Q000503:physiopathology; D006801:Humans; D002479:Inclusion Bodies / Q000378:metabolism / Q000473:pathology; D007381:Intermediate Filament Proteins; D007382:Intermediate Filaments / Q000378:metabolism / Q000473:pathology*; D008297:Male; D008875:Middle Aged; D016472:Motor Neuron Disease / Q000209:etiology / Q000473:pathology / Q000503:physiopathology; D009474:Neurons / Q000378:metabolism / Q000473:pathology*; D020734:Parkinsonian Disorders / Q000209:etiology / Q000473:pathology / Q000503:physiopathology; D010641:Phenotype; D012189:Retrospective Studies; D013116:Spinal Cord / Q000378:metabolism / Q000473:pathology / Q000503:physiopathology
D002352:Carrier Proteins; D007381:Intermediate Filament Proteins; C046643:alpha-internexin