APP and early-onset autosomal dominant Alzheimer disease: More specifically, Breimer and Denny suggested that in Alzheimer’s disease, C99 and, subsequently, Aβ are produced via partial translation of the intact human AβPP mRNA initiating within its coding region at the AUG codon normally encoding Met671 (i.e., via unconventional internal initiation of translation of the intact AβPP mRNA).