Huntington's disease is a neurodegenerative genetic disorder caused by a change in the HTT gene, which codes for a protein called huntingtin. While almost everyone who carries the altered version of the HTT gene will develop a form of Huntington's disease, there is no current cure and imaging biomarkers could be used to support drug development and monitor outcomes in clinical trials.
As part of the TRACK-HD study, which is looking at biomarkers for pre-symptomatic and early Huntington's disease, researchers looked at patients with the mutant HTT gene but no symptoms, patients with early-stage Huntington's disease, and healthy controls, using a number of different measures, including brain imaging.
Imaging showed atrophy (loss) in changes in the grey matter and white matter of the brain, as well as in the whole brain and specific areas of the brain. Of the different measures used, brain magnetic resonance imaging (MRI) was the most consistent measure for disease progression.
"We have identified a subset of measures that do show detectable change over 24 months among people with early-stage manifest HD," said Douglas R. Langbehn, MD, PhD, investigator and professor in the Department of Psychiatry at the University of Iowa in an interview with Medscape Medical News.
Symptoms of Huntington's disease usually show up in middle age and include restlessness, lack of coordination of movements, and problems with mood, thinking and reasoning. Huntington's disease affects lifespan--people usually live for 10-20 years after symptoms begin. There are early-onset and late-onset forms with some differences in rate of progression and symptoms, and brain imaging biomarkers could be a non-invasive way of tracking the progress of the disease and predicting the outcome for different patients. There are currently no treatments that affect the course of the disease, and clinical trials have to rely on the Unified Huntington's Disease Rating Scale, which isn't very sensitive and can require long studies. However, new biomarkers could support and speed up the development of drugs and help to monitor their efficacy.