PPARG and amyotrophic lateral sclerosis: Neurodegenerative diseases are classified in two categories [34], i.e., diseases that present a downregulation of the canonical WNT/β-catenin pathway and an upregulation of PPARγ, such as Alzheimer’s disease [81,82,83], and diseases with an upregulation of the canonical WNT/β-catenin pathway whereas PPARγ is decreased, such as exudative age related macular degeneration [84,85], amyotrophic lateral sclerosis [86], and multiple sclerosis [18].