title: A comparative clinical, pathological, biochemical and genetic study of fused in sarcoma proteinopathies.
abstract: Neuronal intermediate filament inclusion disease and atypical frontotemporal lobar degeneration are rare diseases characterized by ubiquitin-positive inclusions lacking transactive response DNA-binding protein-43 and tau. Recently, mutations in the fused in sarcoma gene have been shown to cause familial amyotrophic lateral sclerosis and fused in sarcoma-positive neuronal inclusions have subsequently been demonstrated in neuronal intermediate filament inclusion disease and atypical frontotemporal lobar degeneration with ubiquitinated inclusions. Here we provide clinical, imaging, morphological findings, as well as genetic and biochemical data in 14 fused in sarcoma proteinopathy cases. In this cohort, the age of onset was variable but included cases of young-onset disease. Patients with atypical frontotemporal lobar degeneration with ubiquitinated inclusions all presented with behavioural variant frontotemporal dementia, while the clinical presentation in neuronal intermediate filament inclusion disease was more heterogeneous, including cases with motor neuron disease and extrapyramidal syndromes. Neuroimaging revealed atrophy of the frontal and anterior temporal lobes as well as the caudate in the cases with atypical frontotemporal lobar degeneration with ubiquitinated inclusions, but was more heterogeneous in the cases with neuronal intermediate filament inclusion disease, often being normal to visual inspection early on in the disease. The distribution and severity of fused in sarcoma-positive neuronal cytoplasmic inclusions, neuronal intranuclear inclusions and neurites were recorded and fused in sarcoma was biochemically analysed in both subgroups. Fused in sarcoma-positive neuronal cytoplasmic and intranuclear inclusions were found in the hippocampal granule cell layer in variable numbers. Cortical fused in sarcoma-positive neuronal cytoplasmic inclusions were often 'Pick body-like' in neuronal intermediate filament inclusion disease, and annular and crescent-shaped inclusions were seen in both conditions. Motor neurons contained variable numbers of compact, granular or skein-like cytoplasmic inclusions in all fused in sarcoma-positive cases in which brainstem and spinal cord motor neurons were available for study (five and four cases, respectively). No fused in sarcoma mutations were found in any cases. Biochemically, two major fused in sarcoma species were found and shown to be more insoluble in the atypical frontotemporal lobar degeneration with ubiquitinated inclusions subgroup compared with neuronal intermediate filament inclusion disease. There is considerable overlap and also significant differences in fused in sarcoma-positive pathology between the two subgroups, suggesting they may represent a spectrum of the same disease. The co-existence of fused in sarcoma-positive inclusions in both motor neurons and extramotor cerebral structures is a characteristic finding in sporadic fused in sarcoma proteinopathies, indicating a multisystem disorder.
authors.affiliation: Queen Square Brain Bank, Institute of Neurology, Queen Square, London WC1N 3BG, UK.
authors.forename: Tammaryn
authors.initials: T
authors.lastname: Lashley
authors.forename: Jonathan D
authors.initials: JD
authors.lastname: Rohrer
authors.forename: Rina
authors.initials: R
authors.lastname: Bandopadhyay
authors.forename: Charles
authors.initials: C
authors.lastname: Fry
authors.forename: Zeshan
authors.initials: Z
authors.lastname: Ahmed
authors.forename: Adrian M
authors.initials: AM
authors.lastname: Isaacs
authors.forename: Jack H
authors.initials: JH
authors.lastname: Brelstaff
authors.forename: Barbara
authors.initials: B
authors.lastname: Borroni
authors.forename: Jason D
authors.initials: JD
authors.lastname: Warren
authors.forename: Claire
authors.initials: C
authors.lastname: Troakes
authors.forename: Andrew
authors.initials: A
authors.lastname: King
authors.forename: Safa
authors.initials: S
authors.lastname: Al-Saraj
authors.forename: Jia
authors.initials: J
authors.lastname: Newcombe
authors.forename: Niall
authors.initials: N
authors.lastname: Quinn
authors.forename: Karen
authors.initials: K
authors.lastname: Ostergaard
authors.forename: Henrik Daa
authors.initials: HD
authors.lastname: Schrøder
authors.forename: Marie
authors.initials: M
authors.lastname: Bojsen-Møller
authors.forename: Hans
authors.initials: H
authors.lastname: Braendgaard
authors.forename: Nick C
authors.initials: NC
authors.lastname: Fox
authors.forename: Martin N
authors.initials: MN
authors.lastname: Rossor
authors.forename: Andrew J
authors.initials: AJ
authors.lastname: Lees
authors.forename: Janice L
authors.initials: JL
authors.lastname: Holton
authors.forename: Tamas
authors.initials: T
authors.lastname: Revesz
mesh_terms: D000328:Adult; D017668:Age of Onset; D000368:Aged; D001921:Brain / Q000473:pathology; D015331:Cohort Studies; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism; D005260:Female; D057174:Frontotemporal Lobar Degeneration / Q000235:genetics / Q000473:pathology / Q000503:physiopathology; D006801:Humans; D002479:Inclusion Bodies / Q000473:pathology*; D007382:Intermediate Filaments / Q000378:metabolism / Q000473:pathology*; D008297:Male; D008875:Middle Aged; D009474:Neurons / Q000166:cytology / Q000473:pathology*; D034702:RNA-Binding Protein FUS / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D025801:Ubiquitin / Q000378:metabolism; D016875:tau Proteins / Q000235:genetics / Q000378:metabolism
chemical_list: D004268:DNA-Binding Proteins; C054369:MAPT protein, human; D034702:RNA-Binding Protein FUS; D025801:Ubiquitin; D016875:tau Proteins