Metabolite Profiling Reveals Predictive Biomarkers and the Absence of β‑Methyl Amino‑l‑alanine in Plasma from Individuals Diagnosed with Amyotrophic Lateral Sclerosis

By employing chip-based capillary zone electrophoresis coupled to high-resolution mass spectrometry, we profiled the plasma metabolome of 134 patients diagnosed with sporadic amyotrophic lateral sclerosis (ALS) (81 males and 53 females) and 118 individuals deemed healthy (49 males and 69 females). The most significant markers (p 13C315N2) spike-in standard, we were unable to detect the exogenous neurotoxic metabolite, β-methylamino-l-alanine, in the free or protein-bound fraction of any of the 252 plasma samples.