Different amyloid proteins include AA amyloid (inflammation-associated), AL amyloid, Beta2-microglobulin, senile cardiac amyloid (prealbumin), beta-amyloid protein or Aβ of Alzheimer’s disease (AD) and Down’s syndrome, and prion diseases with PrP proteins [(including Creutzfeldt-Jakob disease (CJD), Gerstmann-Straussler syndrome (GSS), kuru and animal scrapie] all misfold into beta-sheet insoluble fibrillar deposits (reviewed in Snow and Wight, 1989; Snow and Castillo, 1997). Here, PRNP is linked to Alzheimer disease.