Reduced apolipoprotein ϵ4 allele frequency in the oldest old Alzheimer's patients and cognitively normal individuals
1. G. W. Rebeck, PhD,
2. T. T. Perls, MD,
3. H. L. West, MPhil, 4. P. Sodhi, BA,
5. L. A. Lipsitz, MD and
6. B. T. Hyman, MD, PhD
1. Department of Neurology (Drs. Rebeck and Hyman, and H.L. West and P. Sodhi),Massachusetts General Hospital, Boston, MA; and the Hebrew Rehabilitation Center for Aged (Drs. Perls and Lipsitz), Boston, MA.
Recent genetic studies show that theapolipoprotein E ϵ4 allele (ApoE- ϵ4) is a risk factor for Alzheimer's disease (AD). If ApoE- ϵ4 individuals develop AD as they get older, we would expect a decrease in ApoE- ϵ4 allele frequency withincreasing age. We found a marked decline in ApoE- ϵ4 allele frequency with advancing age in both AD and cognitively normal controls (p < 0.003), although in all age groups the ApoE- ϵ4 allele wasoverrepresented (p < 0.0001). Nonetheless, a few cognitively normal nonagenarians were ApoE- ϵ4 positive. Thus, our data support two new conclusions: (1) the ApoE- ϵ4 associated risk for AD isage-dependent, probably due to censoring by the earlier development of AD in ApoE- ϵ4 individuals, and (2) despite the ApoE- ϵ4 associated risk for AD, it is possible to reach extreme old age with normalcognition.
Impact of sample selection on APOE epsilon 4 allele frequency: a comparison of two Alzheimer's disease samples.
Tsuang D, Kukull W, Sheppard L, Barnhart RL, Peskind E, EdlandSD, Schellenberg G, Raskind M, Larson EB
Geriatric Research, Education, and Clinical Center, Seattle, Washington, USA.
Journal of the American Geriatrics Society [1996, 44(6):704-7]
Type: JournalArticle, Research Support, U.S. Gov't, P.H.S., Comparative Study
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