[Huntington's disease with childhood and adolescent onset: course of disease, clinical presentation and diagnostic challenges].

Huntington's disease (HD) is an autosomal-dominant neurodegenerative disorder caused by a gene mutation in chromosome 4 that leads to an expansion of CAG - triplet repeats. It occurs mainly between the age of 30 and 50. Only less than 10 % of HD patients are younger than 20 years. In contrast to adult patients young HD patients show more often psychiatric and cognitive symptoms at disease onset than chorea. One third of the children with HD develops an epilepsy.We present 6 children diagnosed with HD in different stages of childhood. We describe first symptoms as well as genetic characteristics and other distinctive features.Both, the clinical presentation and the course of HD in childhood differ from HD in adults. In adolescents the clinical symptoms at onset are often psychiatric (like depression or attention deficit disorder). Choreatic movements typical for adult HD patients are missing.Due to the low prevalence of HD in childhood and the variability of clinical symptoms the process of diagnosing HD in children is difficult. Very often the diagnosis is made years after the first symptoms. Early diagnosis, however, is often important for managing social problems and problems in school.