Juvenile Huntington's Disease
When Huntington's Disease was first identified it was thought that the disease "manifests itself only in adult life". It is now known that HD can occur in individuals younger than 20 years of age and this is recognised as Juvenile Huntington Disease. The faulty gene that causes adult onset HD is the same one that causes the juvenile form (and is related to a very high number of CAG repeats 60, 70 or more.) Studies indicate that the incidence of Juvenile HD although very rare is more likely seen in cases where the faulty gene has been inherited from the father (Paternal inheritance).
Juvenile HD is characterised by a movement disorder, which differs from that of affected adults. It is more likely that the child will be very rigid, and it is less likely that he or she will have the chorea (involuntary movements) seen in most adults.
Seizures can be prevalent in about 25%-30% of juvenile cases and there are the same difficulties with swallowing and speech as in adult HD; cognitive and behavioural changes can also be prominent.
Generally the earlier the symptoms start the more rapidly the disease will progress and because of the inherited nature of HD it may be that a parent or other family member will be affected at the same time causing a greater strain for families who are affected.
Some reports indicate that less than 5% of people with HD will have the juvenile form of the disease and onset before the age of 6 is very rare (about less than 1%). Almost all children with HD walk and talk at normal age and symptoms often appear gradually so it can be difficult to differentiate them from normal growing pains.
As in adult HD, Juvenile HD remains incurable and there are no treatments, which can stop or slow down this process.
For more information on Juvenile Huntington's Disease contact:
Huntington's WA (Inc)
Tel: (08) 9346 7599
Juvenile HD Handbook (Adapted from Juvenile Huntington's Disease. HD Society of Canada)
Challenging behaviour in Juvenile HD (UK Fact Sheet)