Background Neurofilament light chain (NFL) is an important protein in the cytoskeleton, and it is generally accepted as a marker of permanent neuronal damage. The NFL level in CSF has gained clinical use as a prognostic marker in neurological diseases like Amyotrophic Lateral Sclerosis, Multiple Sclerosis and Alzheimer’s disease. It has also been suggested to be a marker of disease stage in Huntington’s disease (HD) in two previous studies, with a linear association to levels of mutant Huntingtin.

Aim To validate the proposed role of NFL as a reliable clinical biomarker for disease stage in HD.

Methods CSF samples from manifest HD-patients (n = 12) and premanifest HD-gene expansion carriers (n = 11) were obtained by lumbar puncture. The subjects were assessed with UHDRS total motor score, the cognitive-s test battery, Functional Assessment and Total Functional Capacity to characterise disease stage.

NFL was quantified by ELISA (ng/ml). Control samples obtained in identical fashion (n = 5) were analysed to assess sample quality. A validated standard reference range for NFL measured in CSF is available.

Results Pending. NFL values will be available in July 2016 in time to be presented at the EHDN Plenary Meeting in The Hague.

Conclusion This is a cross sectional study to evaluate CSF biomarkers. Longitudinal sampling is needed to further establish their roll and usefulness. NFL is not a disease-specific biomarker, but is clinically available in many hospital labs, unlike for instance mtHTT assays.