Journal Article

APOE4 homozygosity represents a distinct genetic form of Alzheimer’s disease

Sperling, Reisa, Belbin, Olivia, Vaqué-Alcázar, Lídia, Alcolea, Daniel, Fortea, Juan, Gispert, Juan Domingo, Johnson, Sterling C., Bejanin, Alexandre, Montal, Víctor, Pegueroles, Jordi, Videla, Laura, Lleó, Alberto, Suárez-Calvet, Marc, Dols-Icardo, Oriol

2024

Overview

This study aimed to evaluate the impact of APOE4 homozygosity on Alzheimer’s disease (AD) by examining its clinical, pathological and biomarker changes to see whether APOE4 homozygotes constitute a distinct, genetically determined form of AD. Data from the National Alzheimer’s Coordinating Center and five large cohorts with AD biomarkers were analyzed. The analysis included 3,297 individuals for the pathological study and 10,039 for the clinical study. Findings revealed that almost all APOE4 homozygotes exhibited AD pathology and had significantly higher levels of AD biomarkers from age 55 compared to APOE3 homozygotes. By age 65, nearly all had abnormal amyloid levels in cerebrospinal fluid, and 75% had positive amyloid scans, with the prevalence of these markers increasing with age, indicating near-full penetrance of AD biology in APOE4 homozygotes. The age of symptom onset was earlier in APOE4 homozygotes at 65.1, with a narrower 95% prediction interval than APOE3 homozygotes. The predictability of symptom onset and the sequence of biomarker changes in APOE4 homozygotes mirrored those in autosomal dominant AD and Down syndrome. However, in the dementia stage, there were no differences in amyloid or tau positron emission tomography across haplotypes, despite earlier clinical and biomarker changes. The study concludes that APOE4 homozygotes represent a genetic form of AD, suggesting the need for individualized prevention strategies, clinical trials and treatments. The study on APOE4 homozygosity indicates a genetic variant of Alzheimer’s disease with early symptom onset and distinct biomarker progression, highlighting the need for specialized treatment approaches.

• Publisher: Nature Publishing Group US,Nature Publishing Group
• Subject: 692/53/2423 / 692/617/375/365/1283 / 692/699/375/132 / Age / Alzheimer's disease / Amyloid / Apolipoprotein E4 / Biomarkers / Biomedical and Life Sciences / Biomedicine / Cancer Research / Cerebrospinal fluid / Clinical trials / Dementia disorders / Disease prevention / Down's syndrome / Genetic diversity / Genetic variance / Haplotypes / Homozygosity / Homozygotes / Infectious Diseases / Metabolic Diseases / Molecular Medicine / Neurodegenerative diseases / Neurosciences / Positron emission / Positron emission tomography / Tau protein