Plasma neurofilament light levels show elevation prior to diagnosis of sporadic motor neuron disease in the UK Biobank cohort

Objective Motor neuron disease (MND) is a debilitating neurodegenerative disease with profound unmet need. In pre-symptomatic mutation carriers, elevations in neurofilament light (NfL) precede symptom onset, however, the presence and timing of elevation is much more difficult to study in sporadic cases. Methods Using the UK Biobank cohort, we tested whether plasma NfL predicted risk of diagnosis of sporadic MND using survival analysis. Results We identified 241 MND patients with pre-diagnosis NfL data, of which 203 (84%) lacked predicted loss of function or deleterious missense variants in established ALS genes. A total of 42,752 controls without MND were obtained from a random sample of UK Biobank participants. At two years pre-diagnosis, we found that NfL levels in patients exceeded the 95th percentile of controls and that patients could be discriminated from controls at high accuracy (AUC = 0.95 (95% CI 0.89-1.01)). In participants with hospital record follow-up after study enrollment, a 2-fold increase in NfL levels was associated with a 3.4 fold risk of receiving an MND diagnosis per year (95% CI 2.9-3.9, P = 4 × 10−64)). Discussion Our findings show that NfL can identify sporadic MND as early as 2 years prior to diagnosis. ### Competing Interest Statement All authors are employees of and own stock in Takeda Development Center Americas, Inc. ### Funding Statement This study did not receive any funding ### Author Declarations I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained. Yes The details of the IRB/oversight body that provided approval or exemption for the research described are given below: This research has been conducted using the UK Biobank Resource under Application Numbers 26041 and 65851. The UK Biobank was approved by the North West Multi-centre Research Ethics Committee (MREC) as a Research Tissue Bank (RTB) approval, which allows use by approved researchers without additional ethical clearance. I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals. Yes I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance). Yes I have followed all appropriate research reporting guidelines, such as any relevant EQUATOR Network research reporting checklist(s) and other pertinent material, if applicable. Yes All data used in the present study will be available through the UK Biobank.