title: 18F-FDG PET uptake in the pre-Huntington disease caudate affects the time-to-onset independently of CAG expansion size.
abstract: OBJECTIVE
  To test in a longitudinal follow-up study whether basal glucose metabolism in subjects with a genetic risk of Huntington disease (HD) may influence the onset of manifest symptoms.
  
  
  METHODS
  The study group comprised 43 presymptomatic (preHD) subjects carrying the HD mutation. They underwent a (18)F-FDG PET scan and were prospectively followed-up for at least 5 years using the unified HD rating scale to detect clinical changes. Multiple regression analysis included subject's age, CAG mutation size and glucose uptake as variables in a model to predict age at onset.
  
  
  RESULTS
  Of the 43 preHD subjects who manifested motor symptoms, suggestive of HD, after 5 years from the PET scan, 26 showed a mean brain glucose uptake below the cut-off of 1.0493 in the caudate, significantly lower than the 17 preHD subjects who remained symptom-free (P < 0.0001). This difference was independent of mutation size. Measurement of brain glucose uptake improved the CAG repeat number and age-based model for predicting age at onset by 37 %.
  
  
  CONCLUSIONS
  A reduced level of glucose metabolism in the brain caudate may represent a predisposing factor that contributes to the age at onset of HD in preHD subjects, in addition to the mutation size.
authors.affiliation: Nuclear Medicine Department, S Andrea Hospital, via Vittorio Veneto, 197 La Spezia, Italy. andrea.ciarmiello@asl5.liguria.it
authors.forename: Andrea
authors.initials: A
authors.lastname: Ciarmiello
authors.forename: Giampiero
authors.initials: G
authors.lastname: Giovacchini
authors.forename: Sara
authors.initials: S
authors.lastname: Orobello
authors.forename: Laura
authors.initials: L
authors.lastname: Bruselli
authors.forename: Francesca
authors.initials: F
authors.lastname: Elifani
authors.forename: Ferdinando
authors.initials: F
authors.lastname: Squitieri
mesh_terms: D000328:Adult; D017668:Age of Onset; D001692:Biological Transport; D002421:Caudate Nucleus / Q000000981:diagnostic imaging / Q000378:metabolism*; D005260:Female; D019788:Fluorodeoxyglucose F18 / Q000378:metabolism*; D005500:Follow-Up Studies; D005947:Glucose / Q000378:metabolism; D006801:Humans; D006816:Huntington Disease / Q000000981:diagnostic imaging / Q000235:genetics* / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D049268:Positron-Emission Tomography; D012091:Repetitive Sequences, Nucleic Acid; D055815:Young Adult
chemical_list: D019788:Fluorodeoxyglucose F18; D005947:Glucose