Alzheimer’s, of which there are millions of new cases throughout the world every year and which is the most common type of dementia, is a disease whose causes we still do not fully understand. And among the many research projects on triggering factors there is also a study just published on Nature Medicine.
The results indicate that the APOE4 form of the APOE gene, already “investigated” for some time in the context of Alzheimer’s, is strongly correlated with the risk of onset of the disease. In particular, people whose genome contains a double copy of this form of the gene – called APOE4 homozygotes – have a very high probability of developing the disease and of developing it earlier than those with other variants of the same gene. So much so that homozygosity for APOE4 could represent a new genetic form of the disease.
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I study
The APOE gene codes for a protein known as apolipoprotein E, which, like other apoliproteins, is capable of binding fats present in the blood and plays a role in transporting cholesterol and triglyceride molecules within the bloodstream. Furthermore, apolipoprotein E is correlated with the accumulation of beta-amyloid, the dominant component in amyloid plaques, which in turn represent one of the main microscopic features of Alzheimer’s disease.
Given the link of this gene with the onset of Alzheimer’s, which emerged from many previously published studies, the authors of the new research examined the clinical, pathological and changes related to specific biomarkers in people homozygous for APOE4. Specifically, they used data from over 3 thousand brain donors, of which 273 were APOE4 homozygous, and clinical data from over 10 thousand people, of which 519 were APOE4 homozygous.
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The results
It turns out that virtually all homozygotes for APOE4 have Alzheimer’s disease and already at age 55 have higher levels of biomarkers associated with the disease than individuals with the APOE3 form of the gene. Furthermore, more than 95% of people over 65 who have two copies of the APOE4 gene show abnormal levels of amyloid in the cerebrospinal fluid, a hallmark early pathological feature of Alzheimer’s disease.
“This gene has been known for over 30 years and was known to be associated with a greater risk of developing Alzheimer’s disease – he comments Juan Forteaneurologist at the Dementia Neurobiology Group of the Sant Pau Research Institute (Spain) and first author of the study – But now we know that virtually all individuals with this duplicated gene develop the biological signs of Alzheimer’s.”
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A distinct “genetic form”?
Based on the results obtained, the authors suggest that the genetic variant of the APOE4 gene is not only a risk factor for the onset of Alzheimer’s, but that it may even represent a distinct genetic form of the disease. And the observations collected during the study, the researchers explain, could be useful for the development of targeted preventive strategies: “The data clearly shows that having two copies of the APOE4 gene not only increases the risk, but anticipates the onset of Alzheimer’s – he concludes Alberto Leónresearcher at the Dementia Neurobiology Group of the Sant Pau Research Institute and co-author of the study – reinforcing the need for specific preventive strategies.”
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#Alzheimers #genetic #form
– 2024-05-06 23:51:38
