APP and early-onset autosomal dominant Alzheimer disease: On the basis of the above observations, Breimer and Denny posited that such localization of the AUG codon encoding Met671 of human AβPP is not random, but is rather a reflection of its second (in addition to encoding Met671) physiological function, namely the initiation of translation of AβPP mRNA resulting in the AβPP-independent production of C99 and, potentially, of Aβ in Alzheimer’s disease-affected neurons [120].