IGF2 is a regulator of neurogenesis, synaptic formation and spine maturation in the brain that plays a role in learning and memory functions.71–73 Importantly, reduced IGF2 levels have been reported in the striatum and plasma from HD patients.50 We detected significantly elevated IFG2 levels in late HD compared with controls (P = 0.012), and moderate correlations with TFC (ρ = −0.40), TMS (ρ = 0.40), and SWR (ρ = −0.42) in manHD individuals. Here, IGF2 is linked to Huntington disease.