The Huntington Quality of Life Instrument (H-QoL-I) is a first self-reported specific Health-Related Quality of Life (HR-QoL) instrument developed to assess the QoL of patients suffering from Huntington’s disease. It was originally developed and validated in French and in Italian. The instrument is being validated in 11 languages. This study aims to validate the German, Polish and US versions of H-QoL-I cross-culturally.