The Microbiome of ALS – : Does It Start from the Gut?

Many microorganisms, including thousands of bacterial species referred to as the microbiome, have a daily influence on human health. Over the past few years, a bacterial imbalance termed dysbiosis has been observed in many neurodegenerative diseases, including multiple sclerosis and Parkinson's disease. Scientists made various hypotheses regarding these perturbations, including that the deficiency or excess of certain bacterial species could directly contribute to neurodegeneration and pathogenesis of these diseases through the gut‐brain axis. However, microbiome studies remain complex due to the difficulty in unraveling the role of each microorganism in such a sophisticated environment. Here, we review the state of research on this emerging topic in the ALS field and discuss how bacteria‐host interactions might enable or protect against disease pathogenesis.