Neurofilaments in pre-symptomatic ALS and the impact of genotype

Abstract

Objective. To evaluate serum and cerebrospinal fluid (CSF) levels of phosphorylated neurofilament heavy (pNfH), and to compare these to levels of neurofilament light (NfL), as biomarkers of pre-symptomatic ALS. Design. The study population includes 34 controls, 79 individuals at-risk for ALS, 22 ALS patients, and 14 phenoconverters. At-risk individuals are enrolled through Pre-Symptomatic Familial ALS (Pre-fALS), a longitudinal natural history and biomarker study of individuals who are carriers of any ALS-associated gene mutation, but who demonstrate no clinical evidence of disease at the time of enrollment. pNfH and NfL in serum and CSF were quantified using established enzyme-linked immunosorbent assays. Results. There is a longitudinal increase in serum pNfH in advance of the emergence of clinically manifest ALS. A similar pattern is observed for NfL, but with the absolute levels also frequently exceeding a normative threshold. Although CSF data are more sparse, similar patterns are observed for both neurofilaments, with absolute levels exceeding a normative threshold prior to phenoconversion. In serum, these changes are observed in the 6–12 months prior to disease among SOD1 A4V mutation carriers, and as far back as 2 and 3.5 years, respectively, in individuals with a FUS c.521del6 mutation and a C9ORF72 hexanucleotide repeat expansion. Conclusions. Serum and CSF pNfH increase prior to phenoconversion. In CSF, the temporal course of these changes is similar to NfL. In serum, however, pNfH is less sensitive to pre-symptomatic disease than NfL. The duration of pre-symptomatic disease, as defined by changes in neurofilaments, may vary depending on underlying genotype.

Keywords:

• Amyotrophic lateral sclerosis
• neurofilaments
• biomarkers
• pre-symptomatic
• disease prevention

Acknowledgements

We extend thanks to our research team at the University of Miami for participant recruitment and evaluation (Dr. Volkan Granit, Anne-Laure Grignon, Danielle Dauphin, M. Catalina Fernandez, Danielle Sheldon, Eliana Reyes, Sumaira Hussain, Anne Cooley, Jessica Stark, Dr. Christina Bermudez, Jessica Medina, Ashley Manso) and data management (Christine Clayman); and Christine Stanislaw at Emory University for providing genetic counseling. We are also grateful to Euroimmun for in-kind support through the provision of ELISA kits. Most importantly, we are grateful to all the Pre-fALS participants as well as control and ALS affected participants for their altruism as well as their commitment and contribution to advancing ALS therapy development efforts.

Author Contribution

Table

Declaration of interest

Drs. Benatar and Malaspina have filed a provisional patent entitled: “Determining onset of amyotrophic lateral sclerosis.”

M. Benatar reports grant support from Muscular Dystrophy Association, ALS Association, ALS Recovery Fund, Kimmelman Estate, Target ALS, Eli Lilly & Company, and the National Institutes of Health (NIH) during the conduct of the study. He also reports grant support from FDA, CDC, and DOD; research support from Alexion Pharmaceuticals, UCB, Cytokinetics, Neuraltus, Biogen and Orphazyme A/S; and personal fees from NMD Pharma, Ra Pharmaceuticals, Mitsubishi-Tanabe, Avexis, UCB and Denali outside the submitted work.

J. Wuu reports grant support from Muscular Dystrophy Association, ALS Association, ALS Recovery Fund, Kimmelman Estate, Eli Lilly & Company and the NIH during the conduct of the study; and grant support from FDA, CDC, and DOD, and from Target ALS Foundation outside the submitted work.

V. Lombardi reports no disclosures.

A. Jeromin has received compensation and stock options from Iron Horse Diagnostics, Inc.

R. Bowser reports grants from the ALS Association, the Muscular Dystrophy Association and Target ALS; and personal fees from Mitsubishi-Tanabe outside the submitted work. He has also received compensation and stock options from Iron Horse Diagnostics, Inc.

P. M. Andersen reports grants from the Swedish Research Council, The Swedish Brain Research Foundation, the Knut and Alice Wallenberg Foundation; research support from Orphazyme A/S, Orion Pharma and Biogen; and personal fees from Biogen, Orphazyme A/S, and Hoffman la Roche/Genentech outside the submitted work.

A. Malaspina reports grants from NIH, MND Association UK, NIHR (UK), EU2020.

Additional information

Funding

The study was sponsored by the Muscular Dystrophy Association [Grants #4365 and #172123], the ALS Association [Grant #2015], the ALS Recovery Fund, the Kimmelman Estate, the National Institutes of Health [R01 NS105479], the Knut and Alice Wallenberg Foundation, the Swedish Research Council, and the Swedish Brain Research Foundation. Euroimmun provided pNfH assay kits as in-kind support.