Alzheimer's disease (AD), unlike Huntington's disease or PD, is also linked to several non-metabolic pathway gene sets including Prion diseases and Adipocytokine signaling; leptin peptide, an adipocytokine, is known to affect amyloid beta, a major component of amyloid plaques found in the brains of AD patients [23], [24]. This evidence concerns the gene LEP and prion disease.