APOE4 homozygosity represents a distinct genetic form of Alzheimer's disease
Fortea J, Pegueroles J, Alcolea D, et al. (Montal V co-lead). Nature Medicine, 2024-05
Topic: Amyloid, tau and blood-test diagnosis
Plain-language summary
Analyzing postmortem brain pathology from over 3,200 people plus biomarker data from more than 10,000 more, researchers found that people who inherit two copies of the APOE4 gene variant (about 2-3% of the population) develop Alzheimer's brain changes almost universally and on a predictable timeline starting around age 55, much like known single-gene forms of Alzheimer's. The authors argue this makes APOE4 homozygosity itself a genetic form of Alzheimer's disease rather than just a risk factor.
What this study adds
Evidence grade: High
This is a follow-up (cohort) study. People who inherit two copies of the APOE4 variant almost universally developed Alzheimer's brain changes on a predictable timeline starting around age 55. Reported effect size: Nearly all APOE4 homozygotes showed Alzheimer's pathology by age 55 vs. about half of non-carriers.
Taken from this record’s own fields, not from reading the paper. The grade is assigned from the abstract’s wording; what that means.
Cite this study APA, Vancouver, BibTeX · download .bib or .ris
APA 7th
Fortea, J., Pegueroles, J., Alcolea, D., et al. (2024). APOE4 homozygosity represents a distinct genetic form of Alzheimer's disease. Nature Medicine.
Vancouver
Fortea J, Pegueroles J, Alcolea D, et al. APOE4 homozygosity represents a distinct genetic form of Alzheimer's disease. Nature Medicine. 2024.
BibTeX
@article{fortea2024-3b742ebe,
author = {Fortea, J. and Pegueroles, J. and Alcolea, D. and others},
title = {{APOE4 homozygosity represents a distinct genetic form of Alzheimer's disease}},
journal = {Nature Medicine},
year = {2024}
}
Built from the record alzhub holds for this paper, not looked up. This record has no DOI, so the citation leaves it out. Volume, issue and page numbers are not held in the record. The record's author list ends in “et al.”, so not every author is named. Check the citation against the original before you use it.
Key findings
- Nearly all APOE4 homozygotes in the postmortem dataset showed Alzheimer's brain pathology from age 55 onward, versus about half of non-carriers
- APOE4 homozygotes had consistently high levels of Alzheimer's biomarkers by age 55
- Biomarker changes followed a predictable sequence resembling known genetically determined (autosomal dominant/Down syndrome-associated) forms of Alzheimer's
Why it matters
People who inherit two copies of the APOE4 variant almost universally developed Alzheimer's brain changes on a predictable timeline starting around age 55. The authors argue this makes APOE4 homozygosity itself a genetic form of Alzheimer's disease rather than just a risk factor.
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Study details
- Study designcohort
- Effect sizeNearly all APOE4 homozygotes showed Alzheimer's pathology by age 55 vs. about half of non-carriers
- Evidence strengthHigh
Limitations
Association-based data from cross-sectional/cohort pathology and biomarker sampling, not a controlled experiment; the combined sample size is not reducible to one clean number given overlapping postmortem and biomarker sub-cohorts.
How this study scored 61/100
Published in a top-tier journal, and it is a cohort study following people over time. Scored zero for sample size, studied in people, randomized / blinded and indexed in PubMed because the record does not state it. We have no data on journal's citation record, times cited, citations per year, impact for its field and year, still being cited, senior author's track record, institution's track record, multicenter collaboration and free to read, so those were left out: it earned 38 of the 62 points we could judge it on, which is 61 out of 100.
| Component | Points | Why |
|---|---|---|
| Journal tier | 10 / 10 | Tier 1 — top-tier general journal (Nature Medicine) |
| Journal's citation record | — / 4 | No journal record from OpenAlex — left out of this score |
| Study design | 7 / 12 | A cohort study following people over time |
| Strength of evidence | 5 / 5 | Rated “high” in our summary |
| Peer-review validation | 10 / 10 | Peer-reviewed. Published as an article in a named peer-reviewed journal. |
| How recent | 4 / 5 | 2024 — within 3 year(s) of the newest study here |
| Sample size | 0 / 4 | Participant count not stated — scores zero (not stated in the record — scored 0) |
| Effect reported | 2 / 3 | Effect reported as a number, without an interval or test |
| Studied in people | 0 / 3 | Not stated whether this was studied in people — scores zero (not stated in the record — scored 0) |
| Randomized / blinded | 0 / 2 | No randomization or blinding stated — scores zero (not stated in the record — scored 0) |
| Times cited | — / 7 | No citation count (not found in OpenAlex) — left out of this score |
| Citations per year | — / 5 | No citation count or no year — left out of this score |
| Impact for its field and year | — / 6 | No field-weighted citation impact (OpenAlex has none yet) — left out of this score |
| Cited by studies here | 0 / 6 | No other study in this library cites it |
| Still being cited | — / 4 | No yearly citation counts — left out of this score |
| Senior author's track record | — / 4 | Senior author's record not available — left out of this score |
| Institution's track record | — / 3 | No institution listed in OpenAlex — left out of this score |
| Multicenter collaboration | — / 3 | Institutions not listed — left out of this score |
| Indexed in PubMed | 0 / 2 | No PubMed ID and no DOI — scores zero (not stated in the record — scored 0) |
| Free to read | — / 2 | Access not recorded — left out of this score |
| Points | 38 / 62 | Scored on 11 of 20 parts. We have no data for the rest, so they are left out: 38 of the 62 points we could judge it on is 61 out of 100. |
| Total | 61 / 100 | — |
What each of these 20 components measures, and what this score is not →
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