AD occurs in different forms. Most cases of AD have unknown etiologies and are called sporadic. A small percentage of AD cases, particularly those with early onset, are familial and are inherited. The disease is autosomal dominant linked to mutations in the genes encoding amyloid precursor protein (APP) (124-126) or presenilin proteins (127,128). For late onset sporadic cases, a variety of risk factors have been identified in addition to old age. The apolipoprotein E (apoE) allele is a susceptibility locus with the apoE4 type showing dose-dependent contributions (129). Cardiovascular disease and head trauma are additional risk factors for AD (122). The formulation of effective therapeutic strategies for the treatment of AD rests on the clarification of the mechanisms of neuronal death in this disease.