ABSTRACT
Alzheimer’s disease (AD), a degenerative disorder that attacks the brain and leads to dementia, is one of the most common dementing disorders of old age, affecting nearly 4 million individuals in the US alone. Although aging per se causes neither dementia nor Alzheimer’s disease, it is the most strongly associated risk factor for AD. Family history, or genetic predisposition, is another important risk factor; a history of AD in a first-degree relative increases the odds of developing AD three- to fourfold. Although AD is a distinct disease defined by its characteristic clinical course and pathology, it is a heterogeneous condition with varied manifestations. The scientific enthusiasm about the possible role of amyloid protein in the pathology of AD has been further fueled by the results of molecular genetics studies that have identified genes associated with familial AD on chromosomes 21, 14, 1, and 19.
