APOLIPOPROTEIN-E AND ALZHEIMERS-DISEASE - STRENGTH OF ASSOCIATION IS RELATED TO AGE AT ONSET

Apolipoprotein E (apoE) epsilon 4 allele frequency among Alzheimer's d isease (AD) patients is increased compared to control subjects and is influenced by the presence of other genetic factors and age at symptom onset. We examined the relationship between age at AD symptom onset a nd apoE by comparing the apoE epsilon 4 allele frequency of normal, el derly control subjects (n = 107) to that in AD patients (n = 123), div ided into four age-at-onset periods. Additionally, the distribution of symptom onset ages of AD patients with and without apoE epsilon 4 all eles was determined. We observed increased apoE epsilon 4 allele frequ encies between the AD onset ages of 55 and 75 years, but not at the ex tremes of onset ages (i.e. onset between 45 and 54 years of age and af ter age 75). Our data suggests that having an apoE epsilon 4 allele in creases the likelihood that AD patients will develop symptoms in the m iddle range of onset ages. At the extremes of AD onset ages, non-apoE factors, including other genetic factors and age, are more important d eterminants of risk of developing AD.