title: HTRF analysis of soluble huntingtin in PHAROS PBMCs.
abstract: OBJECTIVE
  We measured the levels of mutant huntingtin (mtHtt) and total huntingtin (tHtt) in blood leukocytes from Prospective Huntington At-Risk Observational Study (PHAROS) subjects at 50% risk of carrying the Huntington disease mutation using a homogeneous time-resolved fluorescence (HTRF) assay to assess its potential as a biomarker.
  
  
  METHODS
  Peripheral blood mononuclear cells from consenting PHAROS subjects were analyzed by HTRF using antibodies that simultaneously measured mtHtt and tHtt. mtHtt levels were normalized to tHtt, double-stranded DNA, or protein and analyzed according to cytosine-adenine-guanine repeat length (CAGn), demographics, predicted time to clinical onset or known time since clinical onset, and available clinical measures.
  
  
  RESULTS
  From 363 assayed samples, 342 met quality control standards. Levels of mtHtt and mt/tHtt were higher in 114 subjects with expanded CAG repeats (CAG ≥ 37) compared with 228 subjects with nonexpanded CAG repeats (CAG <37) (p < 0.0001). Analysis of relationships to predicted time to onset or to phenoconversion suggested that the HTRF signal could mark changes during the Huntington disease prodrome or after clinical onset.
  
  
  CONCLUSIONS
  The HTRF assay can effectively measure mtHtt in multicenter sample sets and may be useful in trials of therapies targeting huntingtin.
authors: From the Massachusetts General Hospital (M.M.-L., R.E.G., J.J.R., H.D.R., S.M., A.B.Y., S.M.H.), MassGeneral Institute for Neurodegenerative Disease, Department of Neurology, Charlestown, MA; University of Rochester Medical Center (S.E., D.O.), Department of Biostatistics and Computational Biology, Rochester, NY; Veterans Administration Hospital (W.M.), Bedford, MA; and Program for Regulatory Science & Medicine (I.S.), Georgetown University, Washington, DC.
authors: Miriam
authors: M
authors: Moscovitch-Lopatin
authors: Rachel E
authors: RE
authors: Goodman
authors: Shirley
authors: S
authors: Eberly
authors: James J
authors: JJ
authors: Ritch
authors: H Diana
authors: HD
authors: Rosas
authors: Samantha
authors: S
authors: Matson
authors: Wayne
authors: W
authors: Matson
authors: David
authors: D
authors: Oakes
authors: Anne B
authors: AB
authors: Young
authors: Ira
authors: I
authors: Shoulson
authors: Steven M
authors: SM
authors: Hersch
mesh_terms: D000328:Adult; D002986:Clinical Trials as Topic; D004311:Double-Blind Method; D005260:Female; D031541:Fluorescence Resonance Energy Transfer / Q000379:methods*; D005625:Frontal Lobe / Q000378:metabolism / Q000473:pathology; D006801:Humans; D000071058:Huntingtin Protein; D006816:Huntington Disease / Q000097:blood* / Q000235:genetics / Q000473:pathology*; D007963:Leukocytes, Mononuclear / Q000378:metabolism*; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D009154:Mutation / Q000235:genetics; D009419:Nerve Tissue Proteins / Q000235:genetics / Q000378:metabolism*; D019370:Observation; D011180:Postmortem Changes; D012189:Retrospective Studies; D019680:Trinucleotide Repeat Expansion / Q000235:genetics
chemical_list: C086055:HTT protein, human; D000071058:Huntingtin Protein; D009419:Nerve Tissue Proteins
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