Mutations on a single gene, the huntingtin gene, are the cause of Huntington’s disease. They lead to an incorrect form of the correspondent protein. With the help of cryo-electron microscopy researchers from the Max Planck Institute of Biochemistry in Martinsried and Ulm University have now decoded the three-dimensional, molecular structure of the healthy human huntingtin protein. This now enables its functional analysis. An improved understanding of the structure and the function of the huntingtin protein could contribute to the development of new treatment methods in the future.