It has been reported that only 5% of AD cases (familial type) is due to Aβ overproduction arising from mutations in the APP gene or in APP processing enzymes, whereas the majority (95%) of so-called sporadic AD cases are likely caused by dysfunctions in Aβ solubility, endocytosis, degradation, transcytosis, and removal [2]. The gene discussed is APP; the disease is Alzheimer disease.