A new two-year longitudinal study reveals how two proteins linked to Huntington's disease - an incurable neurodegenerative disorder - change over time in patients and in as-yet asymptomatic people who carry a mutation that causes the condition. By detailing the dynamics of these disease markers, the results could help clinicians develop tools to predict the course of Huntington's disease and to evaluate new therapeutics in clinical trials. Although there are no treatments that can slow Huntington's disease, researchers theorize that targeting the protein mutant huntingtin (mHTT) may prevent the condition from manifesting in people who carry the causative mutation but do not yet show symptoms. Testing this strategy requires measuring either mHTT or another disease-linked protein named neurofilament light (NfL), but it has been unclear how concentrations of these proteins change as the disease progresses. To investigate, Filipe Rodrigues and colleagues gathered plasma and cerebrospinal fluid samples from 20 controls, 20 mutation carriers, and 40 patients with Huntington's disease. The scientists longitudinally measured mHTT and NfL over two years and discovered that levels of NfL rose much faster and in a different pattern in mutation carriers compared with controls. Furthermore, patients with the highest baseline levels of mHTT and NfL at the start of the study showed a faster progression and more severe brain atrophy after two years. "These insights . . . will be of immediate value in the design and conduct of disease-modifying clinical trials, especially as we enter the era of prevention trials where qualified surrogate end points will be fundamental," the authors conclude.
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Journal
Science Translational Medicine