CYBB and amyotrophic lateral sclerosis: Markers related to oxidative stress have also been recently implicated as prognostic factors in ALS: a recent study showed that patients with a lower activity of NADPH oxidase 2 (NOX2), the main reactive oxygen species-producing enzyme, may have a significant increase in survival, [119] while a recent meta-analysis has demonstrated lower levels of uric acid, one of the most important antioxidants in the blood, in ALS patients compared to controls [120].