Behavioral Symptoms in Premanifest Huntington Disease Correlate with Reduced Frontal CB1R Levels

J Nucl Med. 2019 Jan;60(1):115-121. doi: 10.2967/jnumed.118.210393. Epub 2018 Jun 22.


Many Huntington disease (HD) mutation carriers already have cognitive and psychiatric symptoms in the premanifest (premotor) phase of the disease (pre-HD), but the molecular underpinnings of these symptoms are not well understood. Previous work has shown reduced availability of the cerebral type 1 cannabinoid receptor (CB1R) in manifest HD. Here, we investigated whether CB1R binding is related to cognitive and psychiatric symptoms in pre-HD mutation carriers. Methods: CB1R binding was measured with 18F-MK-9470 (N-[(2S,3S)-3-(3-cyanophenyl)-4-(4-ethoxyphenyl)butan-2-yl]-2-methyl-2-(5-methylpyridin-2-yl)oxypropanamide) PET in 15 pre-HD subjects (8 men, 7 women; age, 39.3 ± 9.9 y), 15 gene-negative controls from HD families (9 men, 6 women; age, 37.0 ± 10.6 y), and 12 community controls (6 men and 6 women; age, 39.9 ± 15.1 y). All subjects also underwent extensive assessment of motor and cognitive function, as well as a behavioral test battery including the Problem Behavior Assessment for HD (PBA-HD), and MRI. Parametric binding images of 18F-MK-9470 were corrected for partial-volume effect. Results: There was no difference in CB1R binding, gray matter volume, cognitive function, or psychiatric scores between gene-negative controls from HD families and community controls, which were therefore pooled to one control group. Compared with controls, pre-HD subjects showed striatal atrophy, a decrease in CB1R binding in the prefrontal cortex, and higher PBA-HD scores on depression, apathy, and irritability (range, P = 0.01-0.005). The PBA-HD scores inversely correlated with CB1R binding in prefrontal regions and cingulate cortex in pre-HD (range: r = -0.64 to -0.72; P = 0.01-0.008). Conclusion: The association between behavioral symptoms and reduced prefrontal CB1R levels may provide new insight into the molecular basis of neuropsychiatric symptoms in pre-HD and suggest new therapeutic avenues.

Keywords: PET; behavioral symptoms; cannabinoid type 1 receptor (CB1R); premanifest HD (pre-HD).

MeSH terms

  • Adult
  • Behavioral Symptoms / complications*
  • Case-Control Studies
  • Cognition
  • Female
  • Gray Matter / diagnostic imaging
  • Gray Matter / pathology
  • Humans
  • Huntington Disease / complications*
  • Huntington Disease / diagnostic imaging
  • Huntington Disease / metabolism*
  • Huntington Disease / physiopathology
  • Image Processing, Computer-Assisted
  • Male
  • Organ Size
  • Positron-Emission Tomography
  • Prefrontal Cortex / diagnostic imaging
  • Prefrontal Cortex / metabolism*
  • Prefrontal Cortex / pathology
  • Receptor, Cannabinoid, CB1 / metabolism*


  • Receptor, Cannabinoid, CB1