The list of neurological conditions in which AQP4 might play a pathophysiological role includes epilepsy [15,16] and neurodegenerative diseases, such as Alzheimer’s disease (AD) [17,18,19,20], amyotrophic lateral sclerosis (ALS) [21,22], Huntington’s disease (HD) [23] and spongiform encephalopathy (SE) [24]. Here, AQP4 is linked to amyotrophic lateral sclerosis.