Are BTEX (Benzene, Toluene, Ethylbenzene and Xylenes) involved in the development of amyotrophic lateral sclerosis?

Air pollution is an environmental factor involved in neuroinflammation, which leads to the progressive neuronal damage that appears in various neurodegenerative diseases. This article reviews the impact on Amyotrophic Lateral Sclerosis (ALS), the most common degenerative motor neuron disease, of exposure to BTEX (benzene, toluene, ethylbenzene, and xylene), aromatic hydrocarbons capable of crossing the blood-brain barrier, with documented neurotoxic effects. Results show that occupational exposure to BTEX has been linked to the incidence of ALS, while the relationship with the exposure in residential environments with high levels of these toxins in outdoor air is not conclusive; sources of BTEX emissions often lead to mixed toxic exposure, making it challenging to assess the specific impact of this group of pollutants. Under the commonly accepted hypothesis that ALS is a disease triggered by the accumulation of multiple steps, BTEX could be the step causing toxic insult, or alternatively, BTEX might play a role in the disease’s progression. However new studies are necessary to determine its involvement in the disease.