Onset and pre-onset studies to define the Huntington's disease natural history

Huntington's disease's (HD) clinical history has not been defined yet. However, many aspects of the most confusing clinical stages, i.e., the first and last disease phases, including the symptom progression and the disease duration, have been better approached after discovery of the responsible gene. The existence of accurate genetic tests, available for affected and pre-symptomatic subjects (i.e., mutation carriers) and the possibility to study transgenic in vivo models, are actually helping us to understand some of the aspects of HD clinical presentation. HD may present with motor symptoms other than chorea, the psychiatric manifestations may represent part of the clinical picture and cognitive deterioration may occur very early in the disease and depend on early cortical involvement. Pre-onset studies are of crucial importance in understanding the temporal sequence of the clinical events. This is also very important for future therapeutic strategies in those diseases initiating late in the life, such as HD.