If your genetic test shows APOE ε3/ε4, what does that actually mean?
We inherit two copies of the APOE gene-one from each parent. The three common forms, called alleles, are ε2, ε3 and ε4.
An APOE ε3/ε4 result simply means that you inherited one ε3 allele and one ε4 allele.
The ε3 allele is the most common form of APOE and is generally used as the reference. The ε4 allele is important because it has been associated with a higher risk of some age-related conditions.
In particular, APOE ε4 is associated with an increased risk of Alzheimer’s disease. It can also influence how the body handles cholesterol and is associated with cardiovascular risk.
But carrying ε4 is not a diagnosis.
It does not mean that you will develop Alzheimer’s disease or cardiovascular disease. And it does not mean that you will necessarily live a shorter life.
It means that you have an inherited risk factor-one piece of information that can help us understand your individual health risks.
APOE is also particularly interesting in longevity research. The ε4 allele is found less often in exceptionally long-lived people, while the ε2 allele is found more often.
This is one reason APOE has become one of the most consistently studied genes in human longevity.
However, genes are only part of the picture. Your health as you age is also influenced by many other factors, including family history, cholesterol levels, blood pressure, metabolic health, lifestyle and environment.
This is why an APOE result should never be interpreted on its own.
For someone with an ε3/ε4 result, the useful question is not: “How long will I live?” but rather: “Does this genetic result identify a risk that I should pay more attention to?” The answer depends on the individual. APOE information should therefore be considered together with established clinical assessment, including lipid profile, cardiovascular and metabolic risk, family history and, when clinically appropriate, cognitive and neurological assessment.
APOE can tell us something about risk. It cannot tell us our future.
