IGF1 and Tremor: Overall, Igf-1r deficiency had no significant effects on lifespan or grip-strength in HD mice, but on affected endophenotypes had opposite effects in male and female mice: In HD females, Igf-1r deficiency was neutral (rotarod, weight) or beneficial (delayed tremor onset), whereas in HD males had neutral (tremor onset) or detrimental effects (worsened rotarod performance and weight loss).