title: Pattern of ubiquilin pathology in ALS and FTLD indicates presence of C9ORF72 hexanucleotide expansion.
abstract: C9ORF72-hexanucleotide repeat expansions and ubiquilin-2 (UBQLN2) mutations are recently identified genetic markers in amyotrophic lateral sclerosis (ALS) and frontotemporal lobar degeneration (FTLD). We investigate the relationship between C9ORF72 expansions and the clinical phenotype and neuropathology of ALS and FTLD. Genetic analysis and immunohistochemistry (IHC) were performed on autopsy-confirmed ALS (N = 75), FTLD-TDP (N = 30), AD (N = 14), and controls (N = 11). IHC for neurodegenerative disease pathology consisted of C9ORF72, UBQLN, p62, and TDP-43. A C9ORF72 expansion was identified in 19.4 % of ALS and 31 % of FTLD-TDP cases. ALS cases with C9ORF72 expansions frequently showed a bulbar onset of disease (57 %) and more rapid disease progression to death compared to non-expansion cases. Staining with C9ORF72 antibodies did not yield specific pathology. UBQLN pathology showed a highly distinct pattern in ALS and FTLD-TDP cases with the C9ORF72 expansion, with UBQLN-positive cytoplasmic inclusions in the cerebellar granular layer and extensive UBQLN-positive aggregates and dystrophic neurites in the hippocampal molecular layer and CA regions. These UBQLN pathologies were sufficiently unique to allow correct prediction of cases that were later confirmed to have C9ORF72 expansions by genetic analysis. UBQLN pathology partially co-localized with p62, and to a minor extent with TDP-43 positive dystrophic neurites and spinal cord skein-like inclusions. Our data indicate a pathophysiological link between C9ORF72 expansions and UBQLN proteins in ALS and FTLD-TDP that is associated with a highly characteristic pattern of UBQLN pathology. Our study indicates that this pathology is associated with alterations in clinical phenotype, and suggests that the presence of C9ORF72 repeat expansions may indicate a worse prognosis in ALS.
authors.affiliation: Center for Neurodegenerative Disease Research (CNDR), University of Pennsylvania School of Medicine, 3rd Floor Maloney Building, 3600 Spruce Street, Philadelphia, PA 19104, USA.
authors.forename: Johannes
authors.initials: J
authors.lastname: Brettschneider
authors.forename: Vivianna M
authors.initials: VM
authors.lastname: Van Deerlin
authors.forename: John L
authors.initials: JL
authors.lastname: Robinson
authors.forename: Linda
authors.initials: L
authors.lastname: Kwong
authors.forename: Edward B
authors.initials: EB
authors.lastname: Lee
authors.forename: Yousuf O
authors.initials: YO
authors.lastname: Ali
authors.forename: Nathaniel
authors.initials: N
authors.lastname: Safren
authors.forename: Mervyn J
authors.initials: MJ
authors.lastname: Monteiro
authors.forename: Jon B
authors.initials: JB
authors.lastname: Toledo
authors.forename: Lauren
authors.initials: L
authors.lastname: Elman
authors.forename: Leo
authors.initials: L
authors.lastname: McCluskey
authors.forename: David J
authors.initials: DJ
authors.lastname: Irwin
authors.forename: Murray
authors.initials: M
authors.lastname: Grossman
authors.forename: Laura
authors.initials: L
authors.lastname: Molina-Porcel
authors.forename: Virginia M-Y
authors.initials: VM
authors.lastname: Lee
authors.forename: John Q
authors.initials: JQ
authors.lastname: Trojanowski
mesh_terms: D048868:Adaptor Proteins, Signal Transducing; D017668:Age of Onset; D000368:Aged; D000369:Aged, 80 and over; D000690:Amyotrophic Lateral Sclerosis / Q000235:genetics* / Q000378:metabolism / Q000401:mortality / Q000473:pathology; D000071183:Autophagy-Related Proteins; D000073885:C9orf72 Protein; D018797:Cell Cycle Proteins / Q000235:genetics / Q000378:metabolism*; D042622:DNA Repeat Expansion; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism; D005260:Female; D057174:Frontotemporal Lobar Degeneration / Q000235:genetics* / Q000401:mortality / Q000473:pathology; D006801:Humans; D002479:Inclusion Bodies / Q000473:pathology; D008297:Male; D008875:Middle Aged; D009154:Mutation / Q000235:genetics; D011506:Proteins / Q000235:genetics / Q000378:metabolism*; D014452:Ubiquitins / Q000235:genetics / Q000378:metabolism*
chemical_list: D048868:Adaptor Proteins, Signal Transducing; D000071183:Autophagy-Related Proteins; D000073885:C9orf72 Protein; C568651:C9orf72 protein, human; D018797:Cell Cycle Proteins; D004268:DNA-Binding Proteins; D011506:Proteins; C405662:UBQLN2 protein, human; D014452:Ubiquitins