In contrast, a single well-documented case of a man with phenotypic DS, partial trisomy of chromosome 21, who lacked triplication of APP and died at 72 years of age without any clinical or pathologic signs of AD, is so-far the strongest evidence that the triplication of this gene is also necessary for the development of early-onset AD in persons with DS [70]. The gene discussed is APP; the disease is Alzheimer disease.