Huntington's disease is the most frequent neurodegenerative disease with a prevalence of fewer than 10 cases per 10,000 inhabitants; the juvenile form is responsible for less than 10% of all cases. Huntington's disease belongs to the group known as "triad syndromes," which evolve with cognitive, motor and neuropsychiatric manifestations. Around 30% of patients debut with behavioral symptoms, which are a major challenge for management by patients, families, and caregivers. Huntington's disease (HD) is reviewed and a case of juvenile onset is reported in this article. The characteristics of juvenile-onset Huntington's disease (HD) differ from those of adult-onset HD, as chorea does not occur, although bradykinesia, dystonia, and signs of cerebellar disorder, such as rigidity, are present, frequently in association with convulsive episodes and psychotic manifestations.