Amyotrophic Lateral Sclerosis (ALS) is a biologically heterogeneous neurodegenerative disease in which irreversible motor
neuron injury often precedes diagnosis by many months. Clinical tools such as ALSFRS-R, manual muscle testing,
and respiratory function remain essential, but these measures are relatively late indicators of ongoing axonal loss. Biomarkers are
therefore central to modern ALS research and care: they can support earlier biologic detection, improve prognostic stratification, enrich
clinical trials, and provide faster evidence of target engagement when testing new therapeutics.123
Across contemporary ALS cohorts, biomarker evidence is strongest for structural axonal injury proteins (especially Neurofilament Light
Chain (NfL)), with growing support for phosphorylated neurofilament heavy chain, inflammatory chitinase
pathways, and composite multi-omic signatures. No single analyte captures all disease states, but integrated biomarker panels are
increasingly useful for mapping disease stage and expected progression speed.256
ALS biomarkers are now used across four practical domains:
These roles are especially important in ALS because disease progression can be rapid, therapeutic windows are narrow, and trial recruitment
is resource-limited. A robust biomarker strategy allows smaller and more informative studies while preserving clinically meaningful
endpoints.156
NfL is the leading blood and CSF biomarker in ALS. Elevated concentrations reflect ongoing large-caliber
axonal degeneration and consistently associate with more aggressive clinical trajectories. In practice, baseline NfL can improve prognostic
counseling and is frequently used for trial stratification. Because blood measurements correlate with CSF values, serial NfL monitoring is
feasible in multicenter settings without repeated lumbar puncture.36
NfL is also informative in presymptomatic or very early disease biology. In familial ALS mutation carriers (including pathways related to
SOD1, C9orf72, and FUS), rising neurofilament levels can precede overt weakness,
supporting prevention-oriented and preconversion trial frameworks.35
pNfH provides complementary information and can capture disease aggressiveness when assays are standardized. Recent clinical studies
continue to support pNfH as a high-value adjunct marker for progression modeling, particularly when interpreted with NfL and baseline
phenotype. Together, NfL and pNfH form the current core of fluid-based ALS axonal injury assessment.679
ALS pathobiology includes substantial innate immune activation involving microglia and
astrocytes. Chitinase pathways, including CHIT1 and related proteins, are increasingly linked to inflammatory
response states and disease burden. These signals are not ALS-specific, but they add meaningful biologic resolution when interpreted
alongside neurofilament and clinical phenotype data.89
GFAP and other glial markers are also under active evaluation, especially for disentangling ALS versus ALS-FTD axis phenotypes and for
defining patients with stronger cortical-glial involvement. Current evidence suggests these markers are most useful as part of multimarker
models rather than stand-alone diagnostic tests.912
Biomarker development in ALS is moving beyond single proteins toward integrated molecular signatures. Circulating RNA and miRNA features, including isomiR-level signals, are being explored for prognostication and subtype discrimination. Early findings are promising, but broader validation and assay harmonization are needed before routine deployment.10
Proteomic and panel-based approaches are similarly advancing. Rather than relying on one analyte, current strategy emphasizes composite
models that combine fluid markers, genetics, imaging, and longitudinal clinical trajectories. This systems-level approach is better aligned
with ALS heterogeneity and may identify biologically coherent subgroups for precision trials.5911
Therapeutic development in ALS increasingly treats biomarkers as decision-enabling evidence. In SOD1-targeted therapy
programs, neurofilament reductions have been used as biologically plausible indicators of reduced neuronal injury burden while awaiting
longer-term clinical separation. Biomarkers do not replace functional endpoints, but they can reduce uncertainty and improve go/no-go
decisions in early-stage development.45
A mature biomarker framework can support:
To realize this potential, assay reproducibility, pre-analytical consistency, and internationally shared calibration standards remain mandatory priorities.56
Despite substantial progress, several important gaps remain:
Near-term progress depends on prospective multicenter cohorts, standardized lab workflows, and preplanned biomarker endpoints in
interventional trials. These steps are also critical for harmonized work across the ALS-FTD Spectrum, where
shared and diverging biology must be disentangled for precision treatment strategies.569
The study of Als Biomarkers And Disease Monitoring has evolved significantly over the past decades. Research in this area has revealed important insights into the underlying mechanisms of neurodegeneration and continues to drive therapeutic development.
Historical context and key discoveries in this field have shaped our current understanding and will continue to guide future research directions.
🔴 Low Confidence
| Dimension | Score |
|---|---|
| Supporting Studies | 12 references |
| Replication | 33% |
| Effect Sizes | 25% |
| Contradicting Evidence | 0% |
| Mechanistic Completeness | 50% |
Overall Confidence: 39%