SAA1 and early-onset autosomal dominant Alzheimer disease: The different C-terminal truncation of the precursor proteins in the two disease variants might suggest an influence of the proteolytic processing of SAA1 protein in the development of the two disease variants, similar to the formation of different types of amyloid deposits by Aβ(1–40) or Aβ(1–42) peptide in the brain of Alzheimer’s disease patients21.