dings that have been made thus far in EOAD and in LOAD.Table 2. Alzheimer's Disease GeneticsChromosome 21Chromosome 14Chromosome 19OnsetEOADEOADLOADRisk factor for developing ADLowHigherHighestSpecific gene(s)APPNot yet isolatedNot yet identified MarkerAPOE-e4Note: Reproduced from Berger & Finkel, 1995, Treating Alzheimer's and other dementias , New York: Springer publishingOther Risk FactorsCorsellis and Brierly (1959) [as cited by Graves & Kukull, 1994] have shown that dementia similar to that seen in AD may occur following a single head injury. In addition, dementia puglistica, (the so called 'punch-drunk syndrome') develops in some boxers. Lower education has also been associated with dementia. Animal studies demonstrate a positive relation between environmental stimulation and dendritic growth. It is also known that dendritic growth in humans continues throughout life. Possibly lower education is related to a lack of mental exercise, which could delay the onset of significant cognitive decline (Graves & Kukull, 1994).Aluminum (Al) has been implicated as a possible neurotoxin, but the evidence is inconclusive (Carson & Butcher, 1992)). Proponents of the Al neurotoxin hypothesis argue that Al has been shown to accumulate in neurons with neurofibrillary degeneration, and that aluminosilicates accumulate in senile plaques. Critics argue that the abnormal accumulation of Al is an effect, not a cause, of brain degeneration. Another controversial risk factor is depression. Four studies have reported a statistically significant association between a history of depression and AD (Graves & Kukull, 1994). The controversy revolves around the idea that depression is possibly an early manifestation of AD.There is some research suggesting that individuals with a weakened immune system may be more susceptible to develop AD. Heyman et al. (1984) [as cited by Graves & Kukull, 1994] have found an increased risk of AD associated with th...
