IGF1‐R → IRS2 signaling in the brain modulates life span and its reduction inhibits symptoms in AD or HD model mice; however, suppression of IR in the brain fails to rescue these symptoms, suggesting distinct functions of IGF1‐R → IRS2 signaling and IR signaling in the brain 63, 64, 65, 66, 67, 68, 69. Here, IRS2 is linked to Huntington disease.