Although we saw an increase in number of more activated microglia in HD, we did not find a microglial upregulation in the expression of the complement genes C1QA/C1QB/C1QC/C3 in HD to correlate with the increased C1q and C3 protein previously identified in the HD caudate associated with loss of corticostriatal synapses [28]. Here, C1QA is linked to Huntington disease.