Juvenile onset Huntington’s Disease (JoHD) is a very rare, early-onset form of Huntington´s Disease (HD) where symptoms begin before the age of 21. JoHD is thought to account for around 5% of all HD cases, which can make dealing with the disease an isolating experience.
Most people who have JoHD have very high CAG repeats in the HTT gene, usually inherited from the father (although it can also be inherited from the mother). JoHD typically has a more rapid progression than HD, although there is a lot of variability between cases. There is no cure for JoHD, with treatment options focused on controlling symptoms and increasing quality of life.
People with JoHD often experience symptoms that are quite different from HD. It is less common to have chorea and more common to experience stiffness and rigidity. Other common symptoms include clumsiness, problems with speech, a decline in cognitive function and behavioural changes. Another feature of JoHD is seizures, thought to be present in around 30% of cases, while almost never being seen in HD. More information about JoHD can be found here.
Research into JoHD has been hindered by its rarity and, to date, no clinical trials have included JoHD patients. This is being addressed by the Huntington’s Disease Youth Organization (HDYO) who have set up JOIN-HD – an international registry for families affected by JoHD. Patient registries are known to be an effective way to move research forward, particularly in rare diseases. The aims of JOIN-HD are to build a global community of families affected by JoHD, to increase knowledge of the disease and to facilitate future research. More information about JOIN-HD can be found here.