BACKGROUND: The juvenile form of Huntington's disease (HD) is a rare disorder. There are no population-based estimates of either its incidence or prevalence in any population in the world. The present study was undertaken to estimate the frequency of juvenile HD in the UK and to examine the range of pharmacological treatments used in its management. METHOD: The records of individuals under the age of 21 who had recorded diagnoses of HD were retrieved from the General Practice Research Database from 1990 through 2010. From these data estimates of incidence and prevalence were made as well as the specific treatments used in the treatment of its physical and psychological manifestations. RESULTS: 12 incident and 21 prevalent patients with juvenile HD were identified. The 21 prevalent cases included the 12 incident cases. The minimum population-based estimate of incidence is 0.70 (95% CI 0.36 to 1.22) per million patient-years. The minimum estimate of prevalence is 6.77/million (95% CI 5.60 to 8.12) per million patient-years. Patients were most frequently prescribed antidepressants, hypnotics, antipsychotics and treatments for motor abnormalities. CONCLUSIONS: In the UK, juvenile HD is an extremely rare and complex disorder. The prescribing data demonstrate that the clinical management of juvenile HD is undertaken with no formal evidence base for the efficacy or safety of the treatments used. Research into the safety and efficacy of appropriate therapies is urgently required to offset the haphazard nature of prescribing. Multinational collaboration will be necessary to enrol sufficient numbers. Exploratory studies, though, should begin now.