Huntington’s disease is a progressive, fatal neurodegenerative disorder that is caused by mutations in one specific gene called huntingtin (Htt). In the 20-plus years since the Htt gene was identified, researchers have focused on the protein encoded by the Htt gene, called Httex1. This protein accumulates in the brains of Huntington’s disease patients, and the prevailing hypothesis has been that it undergoes a dramatic structural change when a repetitive tract of the amino acid glutamine mutates into an aberrantly long region known as the mutationally expanded polyglutamine (polyQ) tract.