Biofluid Biomarkers of Amyotrophic Lateral Sclerosis

Amyotrophic lateral sclerosis (ALS) is an adult-onset degenerative disease that is characterized by the progressive, irreversible loss of upper and lower motor neurons. It is a highly heterogeneous disease and variability in age of onset, site of onset, rate of disease progression, and survival between individuals present significant challenges for diagnosis and clinical care. Research into understanding the cause for ALS, and the clinical management of the disease is limited in part due to the absence of specific, sensitive biomarkers for the disease. To date, studies aimed at identifying reliable and specific biomarkers for ALS have revealed blood, cerebrospinal fluid (CSF), and urine markers as being useful. Here, we summarize some of the most promising fluid biomarkers identified to date, and discuss their proposed utility for improving our approach to ALS diagnosis, care, and research. Overall, while most studies into biomarkers for ALS explore singlemarker utility, accurate profiling of individuals with ALS is likely to require a panel of complementary biomarkers providing insight into multiple aspects of the disease.