Serum and cerebrospinal fluid biochemical markers of ALS

To date there is no satisfactory serum or cerebrospinal fluid (CSF) metabol ic marker with which to identify patients with ALS, The goal of finding a s uitable marker will be more feasible following the identification of define d subgroups of patients with ALS. Some aspects of neurotransmitter chemistr y in CSF seem worthy of further investigation, in particular, clarification of whether there is a significant elevation of CSF glutamate in a subgroup of patients and whether there are robust alterations in the noradrenaline transmitter system. It seems unlikely, in the face of present evidence, tha t the presence of aberrant exitatory amino acid transporter I transcripts i n CSF will prove to be a useful marker of ALS. Increased levels of 3-nitrot yrosine and neurofilament light in CSF, while not entirely disease-specific for ALS, may nevertheless prove useful confirmatory markers of the disease and its progression.