Cited by 1,366Dementia and Cognitive Impairment ResearchAlzheimer's disease research and treatmentsCancer-related cognitive impairment studies

The DOI matches its Crossref record; 43 of the 44 references it cites were found in a registry or an index; none of the 59 sources its claims cite is checked for support yet.

Preclinical Evidence of Alzheimer's Disease in Persons Homozygous for the ε4 Allele for Apolipoprotein E

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Abstract

BACKGROUND: Variants of the apolipoprotein E allele appear to account for most cases of late-onset Alzheimer's disease, and persons with two copies of the epsilon 4 allele appear to have an especially high risk of dementia. Positron-emission tomography (PET) has identified specific regions of the brain in which the rate of glucose metabolism declines progressively in patients with probable Alzheimer's disease. We used PET to investigate whether these same regions of the brain are affected in subjects homozygous for the epsilon 4 allele before the onset of cognitive impairment. METHODS: Apolipoprotein E genotypes were established in 235 volunteers 50 to 65 years of age who reported a family history of probable Alzheimer's disease. Neurologic and psychiatric evaluations, a battery of neuropsychological tests, magnetic resonance imaging, and PET were performed in 11 epsilon 4 homozygotes and 22 controls without the epsilon 4 allele who were matched for sex, age, and level of education. An automated method was used to generate an aggregate surface-projection map that compared regional rates of glucose metabolism in the two groups. RESULTS: The epsilon 4 homozygotes were cognitively normal. They had significantly reduced rates of glucose metabolism in the same posterior cingulate, parietal, temporal, and prefrontal regions as in previously studied patients with probable Alzheimer's disease. They also had reduced rates of glucose metabolism in additional prefrontal regions, which may be preferentially affected during normal aging. CONCLUSIONS: In late middle age, cognitively normal subjects who are homozygous for the epsilon 4 allele for apolipoprotein E have reduced glucose metabolism in the same regions of the brain as in patients with probable Alzheimer's disease. These findings provide preclinical evidence that the presence of the epsilon 4 allele is a risk factor for Alzheimer's disease. PET may offer a relatively rapid way of testing future treatments to prevent Alzheimer's disease.

Overview

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TL;DR

In cognitively normal late-middle-aged ε4 homozygotes with a family history of probable Alzheimer's disease, PET showed reduced glucose metabolism in the same posterior cingulate, parietal, temporal, and prefrontal regions as in probable Alzheimer's disease, plus additional prefrontal reductions. These findings provide preclinical evidence that the ε4 allele is a risk factor for Alzheimer's disease and suggest PET may help test prevention therapies.

Key findings

  • Among 11 ε4 homozygotes and 22 non-ε4 controls matched for sex, age, and education, neuropsychological tests showed no significant differences in verbal memory, visual memory, naming, or visuospatial/constructional skills; MMSE scores were 29.4±0.8 vs. 29.8±0.6.
  • PET showed no significant whole-brain glucose metabolism difference (5.1±1.0 vs. 5.2±0.8 mg/min/100 g, P=0.62) or pontine difference (5.0±1.0 vs. 5.0±0.7, P=0.90), but ε4 homozygotes had significant bilateral reductions in the same posterior cingulate, parietal, temporal, and prefrontal regions as probable Alzheimer's disease; the text reports a maximal posterior cingulate z score of 8.26 (P<0.001), while Table 4 lists z=6.58 for posterior cingulate.
  • ε4 homozygotes also had significant reductions in additional prefrontal regions (maximal z=4.76, P<0.001 without correction for multiple comparisons), which the authors suggest may reflect accelerated aging.
  • One ε4 homozygote had neuropsychological evidence of mild cognitive impairment and the greatest metabolic reductions; excluding his data only minimally affected group means, and reductions remained.

Methods

  • Apolipoprotein E genotypes were established in 235 volunteers aged 50 to 65 who reported a family history of probable Alzheimer's disease in at least one first-degree relative; 12 ε4 homozygotes were identified, and 11 underwent imaging.
  • For each ε4 homozygote, 2 controls without the ε4 allele (6 ε2/ε3 and 16 ε3/ε3) were matched for sex, age within 3 years, and education within 2 years; subjects had neurologic and psychiatric evaluations, a neuropsychological battery, MRI, and FDG PET.
  • An automated three-dimensional stereotactic surface-projection algorithm compared regional glucose metabolism in ε4 homozygotes vs. controls and superimposed results on a prior probable-Alzheimer's disease map (37 patients vs. 22 normal controls); a critical z score of 4.32 identified voxels significant after correction for 278 resolution elements (P<0.05), with post hoc unpaired two-tailed t-tests.

Limitations

  • The paper states the findings should be considered preliminary; no attempt was made to address the combined effect of atrophy and partial-volume averaging on whole-brain or regional measurements.
  • The paper states that apolipoprotein E genotypes cannot predict whether or when Alzheimer's disease will develop, and that prospective longitudinal studies have not yet specified genotype-specific risks, onset ages, or attributable fractions; genotype-specific preventive therapies have not been identified.
  • Evident from the text: the imaging sample was small (11 ε4 homozygotes vs. 22 controls), the design was cross-sectional without longitudinal follow-up, and one ε4 homozygote had mild cognitive impairment and was excluded in a sensitivity analysis.

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Integrity signals

Registry

Crossref · 10.1056/nejm199603213341202

Cites

43 of 43 references verified0 citation errors · 0 not checkable

Statistics

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Claims the paper makes

29 Not checked yet · 16 Own result · 10 Own interpretation · 3 Own method · 1 No basis given

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Show all 38 claims

  • It may state two separate claims as one. 8
  • Probably not a substantial claim. 15
21 of 21
  • The paper relies on this without support.

    Cognitively normal e4 homozygotes in late middle age are in a presymptomatic stage of Alzheimer's disease.

    “we found that the presymptomatic e4 homozygotes had significantly reduced rates of glucose metabolism in the same parietal, temporal, prefrontal, and posterior cingulate regions as patients with probable Alzheimer's disease.”
  • The paper relies on this without support.

    Prospective, longitudinal studies of the general population have not yet specified the risk of Alzheimer's disease associated with each apolipoprotein E genotype, the mean age and variety of ages at the onset of dementia for each genotype, or the percentage of cases of Alzheimer's disease that are attributable to variants of the apolipoprotein E allele.

    “Prospective, longitudinal studies of the general population have not yet specified the risk of Alzheimer's disease associated with each apolipoprotein E genotype, the mean age and variety of ages at the onset of dementia for each genotype, or the percentage of cases of Alzheimer's disease that are attributable to variants of the apolipoprotein E allele.”
  • The paper relies on this without support.

    Genotype-specific preventive therapies have not yet been identified that might outweigh the psychological and social risks involved in making predictions about such a catastrophic illness.

    “Genotype-specific preventive therapies have not yet been identified that might outweigh the psychological and social risks involved in making predictions about such a catastrophic illness.”
  • The paper relies on this without support.

    The association between the e4 allele and Alzheimer's disease has been observed internationally in about 100 clinics.

    “an association that has now been observed internationally in about 100 clinics.”
4 of 4

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Citations

Cites

Show all 44 references

Research works printed but not linked: 11

  1. Roses AD, 1995, J NIH Res, 7, 51
  2. Mielke R, 1994, Dementia, 5, 36
  3. Minoshima S, 1995, J Nucl Med, 36, 1238
  4. Pietrini P, 1993, Dementia, 4, 94
  5. Spitzer RL, Williams JBW, Gibbon M, First MD. User's guide for the structured clinical interview for DSM-III-R (SCID). Washington, D.C.: American Psychiatric Press, 1990.
  6. Minoshima S, 1994, J Nucl Med, 35, 1528
  7. Salmon E, 1991, Acta Neurol Belg, 91, 288
  8. Loessner A, 1995, J Nucl Med, 36, 1141
  9. Davignon J, 1987, Trans Am Clin Climatol Assoc, 99, 100
  10. Wisniewski T, 1994, Am J Pathol, 145, 1030
  11. Kaplitt MG, 1995, Abstr Soc Neurosci, 21, 1008

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Metadata

Authors
Reiman, E. M., Caselli, R. J., Yun, L. S., Chen, K., Bandy, D., Minoshima, S., Thibodeau, S. N., & Osborne, D.
Affiliations
  • University of Arizona (US)
  • Mayo Clinic in Arizona (US)
  • University of Michigan (US)
  • Mayo Clinic (US)
Venue
New England Journal of Medicine
Published
1996-03-21
Volume
334
Issue
12
Pages
752-758
ISSN
  • 0028-4793 (ISSN-L)
  • 1533-4406
OpenAlex
W2023121717
Cited by
1,366
References
44
Citations by year
2026: 15 · 2025: 10 · 2024: 20 · 2023: 28 · 2022: 28 · 2021: 27 · 2020: 30 · 2019: 30 · 2018: 40 · 2017: 41 · 2016: 42 · 2015: 37 · 2014: 53 · 2013: 56 · 2012: 64
FWCI
42.63
Type
journal article
Language
en
Open access
Locations
  • New England Journal of Medicine (publishedVersion)
  • PubMed (publishedVersion)
Funders
  • American Academy of Neurology
  • National Institutes of Health
Topics
  • Health Sciences › Medicine › Psychiatry and Mental health › Dementia and Cognitive Impairment Research
  • Life Sciences › Neuroscience › Cellular and Molecular Neuroscience › Alzheimer's disease research and treatments
  • Health Sciences › Medicine › Oncology › Cancer-related cognitive impairment studies
Keywords
Alzheimer's disease, apolipoprotein E, ε4 allele, homozygosity, preclinical Alzheimer's disease, glucose metabolism, positron emission tomography, brain glucose hypometabolism, family history of Alzheimer's disease, prefrontal cortex, posterior cingulate cortex, parietal cortex, temporal cortex, normal aging, genetic risk factors
MeSH terms
Aged, Alleles, Alzheimer Disease, Apolipoproteins E, Brain, Female, Genotype, Glucose, Homozygote, Humans, Image Processing, Computer-Assisted, Male, Middle Aged, Neuropsychological Tests, Tomography, Emission-Computed, Case-Control Studies

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