Article Text
Abstract
Background In the Netherlands live approximately 1700 symptomatic Huntington Disease (HD) patients. Juvenile-onset Huntington Disease (JoHD) refers to HD patients with symptom onset before 21 years. Whereas adult-onset HD patients participate in several therapeutic trials, JoHD patients are far behind in eligibility for these trials and clinical and pathophysiological characterization.
Aims Clinical characterization of a large JoHD cohort and enabling future clinical trials in the JoHD population.
Methods We started HD-JUNIOR, a national registry for patients with JoHD. We collect retrospective demographic and clinical data from living and deceased JoHD patients and prospective baseline questionnaires and longitudinal personal and contact data from living JoHD patients.
Results In the Netherlands, from 2001 to 2021, a total of 115 out of 2231 HD expanded repeat carriers (CAG ≥40) had a HTT CAG repeat ≥51 (≥5% JoHD likelihood), of which 14 had a CAG repeat ≥60 and 3 ≥80. Clinical data is collected from 28 patients with a diagnosis of JoHD of which 9 had an age at onset ≤10 years. Of these 28 patients 10 are alive and 1 is still below 18 years of age and therefore referred to as Paediatric Huntington Disease (PHD). Questionnaire, personal and contact data was collected for 8 of the 10 living participants.
Conclusions JoHD and PHD patients are extremely rare, representing less than 1% of HD cases in the Netherlands. A national registry is therefore of utmost importance. International collaborations are needed to fully utilize possibilities for prospective trials in JoHD and PHD patients.