Finally, it is important to note that indictment of cycasin/MAM as a potential etiologic agent in ALS-PDC does not exclude a role for other cycad chemicals, including β-N-methylamino-L-alanine [12]; rather, it spurs the search for chemically related compounds that may play a role in sporadic forms of other tauopathies, including AD. This evidence concerns the gene PDC and Alzheimer disease.