FOXO3 rs9400239 and Longevity: What Your Genotype Means

Oct 4

3 min read

The FOXO3 rs9400239 variant is studied for its possible connection with human longevity. Research has associated the T allele with reaching advanced age in some study populations, but a DNA result cannot tell you how long you will live or whether you will reach a particular age [R, R].

FOXO3 helps regulate how cells respond to signals involved in stress, metabolism, and maintenance. That biology makes the gene interesting to aging researchers, but the effect of any one common variant is only part of a much larger picture.

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What Does the FOXO3 Gene Do?

FOXO3—also called FOXO3A—provides instructions for making a transcription factor. Transcription factors help regulate the activity of other genes. FOXO3 is involved in cellular responses to nutrient and stress signals and has been studied in pathways related to metabolism, cell maintenance, and aging [R].

Researchers study FOXO3 because its activity connects with biological processes that change across the lifespan. Findings from cells and animal models help explain why the gene may matter, but they do not show that one human genotype controls aging or determines an individual’s health.

What Is the rs9400239 Variant?

Rs9400239 is a single-nucleotide polymorphism, or SNP, in the FOXO3 region. It does not change the amino-acid sequence of the main FOXO3 protein. Research has located it within the 5′ untranslated region of a FOXO3 transcript called FOXO3A-Short, which is one possible route by which the variant or nearby genetic variation could influence gene regulation [R].

FOXO3 rs9400239 Genotypes: CC, CT, and TT

Genotype	What it means
CC	No T allele. This is not evidence of impaired FOXO3 function or reduced lifespan.
CT	One T allele. The T allele has been associated with longevity in population research.
TT	Two T alleles. The T allele has been associated with longevity in population research.

These descriptions summarize the research direction for rs9400239. They do not rank people’s health or worth, and they should not be read as a personal forecast. People with each genotype can live long or short lives for many reasons that this one marker cannot capture.

What Has Research Found About FOXO3 rs9400239?

A Danish study found an association with reaching advanced age

A 2010 study compared 1,089 people from the Danish 1905 birth cohort with 736 middle-aged adults. Researchers tested 15 FOXO3A SNPs. Rs9400239 was among the variants associated with longevity after correction for multiple comparisons in the oldest-old versus middle-aged analysis. However, none of the tested variants remained statistically significant after correction when researchers examined survival during follow-up of the oldest-old group [R].

A later study examined a possible biological mechanism

A 2023 study investigated a short FOXO3 transcript and rs9400239. In a Danish twin cohort, researchers found that the T allele was associated with faster peripheral glucose clearance during an insulin-infusion test. Laboratory experiments also explored how the transcript and allele related to glucose use in muscle cells [R].

Results depend on the population and study design

A meta-analysis of variants in the insulin and insulin-like growth factor pathway reported an association between rs9400239 and longevity in long-lived men, with a different strength of association in centenarian groups. The findings illustrate that results can vary with the population studied, the age comparison, and the definition of longevity [R].

Does FOXO3 rs9400239 Predict How Long You Will Live?

No. FOXO3 rs9400239 cannot predict an individual’s lifespan. It cannot tell you whether you will reach 90 or 100, assign a number of extra years, or determine your pace of aging. Lifespan and healthy aging are influenced by many genetic and non-genetic factors, including other genes, health conditions, environment, behavior, access to care, and chance. A single common variant is only one small piece of that complex picture.

Can You Find FOXO3 rs9400239 in Raw DNA Data?

Some consumer DNA files include rs9400239, but marker coverage varies by testing provider and chip version. GenesUnveiled reports the FOXO3 result when the required genotype is present and readable in the active file. If the marker is missing or recorded as a no-call, the result may not appear.

You can explore the FOXO3 entry in GeneExplorer to see how the selected marker is presented. For a broader explanation of how GenesUnveiled evaluates genetic findings, read How We Build DNA Reports.