Huntington's disease: new aspects on phenotype and genotype.

Huntington's disease typically presents with involuntary movements, cognitive decline and behavioural abnormalities; however, new data show a greater spectrum and more complexity in the mode of presentation than previously appreciated. On one hand efforts are under way to better assess all aspects of the evolving phenotype over the course of the disease, on the other hand large cohorts have been prospectively followed-up and similar efforts are now being started in China. In this communication, we briefly review the most salient findings from the last couple of years. The recently established large cohorts allow the performance of accurate studies examining correlation of genetic polymorphisms with specific aspects of the phenotype thus allowing for some mechanistic insight into the causes of phenotypic variation. While Huntington's disease is the most frequent hereditary cause of chorea, other disorders with similar clinical phenotypes, including neuroacanthocytosis, are now better known, including a better understanding of the primary cause as well as the pathophysiology at the molecular level. Studies on the mechanisms of disease in these different disorders may shed light on the respective pathomechanisms and may open new approaches to a better understanding and additional treatment options for choreatiform neurodegenerative disorders.