HTT and Huntington disease: Regardless, beyond the interpretation of the role played by the HTT gene in the development of bipolar symptoms, the identification of IA carriers among this Italian cohort of bipolar patients has important implications for both patients and their families: patients can be at risk of developing a complete HD phenotype [11,13], and family members should be made aware of their increased risk of developing behavioral disturbances [10] or inheriting a pathological expanded HTT gene [6].