EPHX2 Genotype

Tucked into a single gene on chromosome 8 sits one of the body's quieter rheostats for inflammation, blood vessel tone, and how cells respond to stress. EPHX2 (epoxide hydrolase 2) makes an enzyme called soluble epoxide hydrolase, and the version you inherit can nudge that rheostat slightly higher or lower for life.

This is a once-in-a-lifetime genetic test, not a moving number on a lab report. The point is not to discover a single answer about your health, but to know whether you carry a variant that subtly tilts your odds toward heart disease, kidney injury, certain metabolic conditions, or specific neuropsychiatric outcomes, so you can adjust everything else accordingly. No major professional society currently recommends EPHX2 genotyping for routine clinical decision-making, so results are best used alongside standard prevention strategies, not as a substitute for them.

What This Gene Actually Does

EPHX2 codes for soluble epoxide hydrolase, an enzyme that breaks down a family of protective lipid signals called epoxyeicosatrienoic acids. Those lipid signals widen blood vessels and dampen inflammation. When the enzyme is more active, those calming signals get broken down faster, shifting the balance toward narrower vessels and more inflammation.

The enzyme is found throughout the body, with the highest levels in the liver and kidney, and meaningful activity in the heart, brain, blood vessels, fat tissue, and immune cells. Because the protein touches so many systems, variants in EPHX2 have been studied across a wide range of conditions, from coronary disease and stroke to kidney injury, diabetes in pregnancy, and depression.

Which Variants Matter Most

Researchers have identified a handful of single-letter changes in EPHX2 that meaningfully shift enzyme activity. Three variants, known as K55R, C154Y, and E470G, tend to push the enzyme to work harder. Two others, R287Q and a small insertion called 402InsR, slow it down. K55R and R287Q are the two most studied in the general population. Their frequency varies substantially by ancestry: in the ARIC cohort, for example, the K55R variant allele frequency in Caucasian participants was around 15 to 21 percent, meaning a meaningful share of people of European ancestry carry at least one copy, while frequencies in African American and other populations differ.

None of these is a high-impact variant the way a familial hypercholesterolemia gene is. The effects on disease risk are real but modest, and they often depend on ancestry, environment, and other risk factors. This test is most useful as one piece in a larger risk picture, not a verdict on its own.

Heart Disease Risk

In the Atherosclerosis Risk in Communities (ARIC) study, Caucasian carriers of the higher-activity K55R variant had about 45 percent higher risk of developing coronary heart disease compared with non-carriers (hazard ratio 1.45, 95 percent confidence interval 1.05 to 2.01). The same association was not seen in African American participants, a reminder that variant effects can vary by genetic background. Subsequent studies have not consistently replicated this finding: a German study of patients undergoing coronary intervention found no association between K55R and coronary disease, and a meta-analysis of R287Q and coronary artery disease was also null, which fits the picture of EPHX2 as a modest susceptibility gene rather than a strong driver.

Other EPHX2 variants have been linked to coronary artery calcification, a direct imaging measure of plaque in the heart's arteries. In studies of African Americans and Europeans with diabetes, a haplotype tagged by R287Q was tied to more coronary calcium, and additional variants were associated with calcified plaque in carotid and coronary arteries.

A large Danish study of nearly 42,000 people found no overall increase in ischemic stroke, heart attack, or ischemic heart disease in carriers of activity-reducing variants. The takeaway is that EPHX2 is a susceptibility gene, not a switch. It nudges risk in some populations and conditions, but does not, on its own, determine whether you develop heart disease.

Stroke Risk

The same ARIC cohort identified two common EPHX2 haplotypes with opposite relationships to ischemic stroke, meaning some versions of the gene appear to raise risk while others appear to lower it. A European study of white adults found three single-letter variants linked to higher ischemic stroke risk, particularly the large-vessel type. Research in southeast China found that the G860A change (the R287Q variant) was tied to higher stroke risk for AA and AG carriers, while the GG version appeared protective.

The pooled evidence has shifted over time. A 2016 meta-analysis of nearly 7,800 stroke cases and 56,500 controls examining the rs751141 variant found no significant pooled association with ischemic stroke. A more recent 2025 meta-analysis that added newer studies did find a modest but statistically significant association (pooled odds ratio about 1.17, 95 percent confidence interval 1.05 to 1.30). The signals are real in some cohorts but inconsistent across populations, which is typical for a susceptibility gene.

Kidney Injury and Transplant Outcomes

The higher-activity K55R variant was independently linked to acute kidney injury after cardiac surgery in white patients without preexisting chronic kidney disease, with a clear step-wise pattern as carrier status increased. In that study, heterozygotes had about a two-fold higher risk and homozygotes a markedly higher risk than non-carriers.

In kidney transplant recipients, a 3' untranslated region variant called rs1042032 mattered on both sides of the operation. Both recipient and donor GG genotype was tied to worse graft function and a higher chance of acute rejection, suggesting that EPHX2 status can shape how well a transplanted kidney settles in and performs.

Diabetic Kidney Disease and Long-Term Mortality

In a roughly 7-year study of 118 people with diabetic chronic kidney disease, those carrying two A copies of a variant called rs11780592 had more albumin in their urine, higher oxidized LDL, thicker carotid artery walls, higher blood pressure, and meaningfully higher all-cause mortality (multivariate hazard ratio 2.61, 95 percent confidence interval 1.32 to 5.17). For someone already living with diabetic kidney disease, that genotype identifies a subgroup with a more aggressive trajectory of vascular and oxidative damage.

Diabetes in Pregnancy

In a Chinese cohort of pregnant women, an EPHX2 missense variant called rs57699806 was tied to higher risk of gestational diabetes and higher post-glucose-load blood sugar. If you are planning a pregnancy and have a family history of glucose problems in pregnancy, this kind of variant is part of the genetic background that may shape your risk.

Mental Health Associations

Several rare and common EPHX2 variants have been linked to anorexia nervosa in sequencing and replication cohorts, and some of those variants appear to change how cholesterol and body mass index relate to each other. The connection makes sense given the enzyme's role in lipid handling, though the effect is modest and far from deterministic.

In major depressive disorder, EPHX2 variants interacted with impulsivity to influence changes in depression severity and suicide risk over time. A separate machine-learning study found that adding EPHX2 genotypes to clinical and cognitive data improved the ability to identify people at higher risk of suicide attempts. These are research signals, not clinical screening tools, but they hint at where this gene may eventually contribute to mental health risk stratification.

Vascular Function in Healthy Adults

Even before disease develops, EPHX2 genotype seems to shape how blood vessels respond to a challenge. In healthy volunteers, K55R and R287Q genotypes changed forearm vasodilator responses, supporting the idea that the enzyme is part of normal vascular regulation, not just disease biology. This helps explain why the same gene shows up in studies of coronary disease, stroke, kidney injury, and blood pressure.

Why a Single Result Is Permanent, but Action Is Not

Your EPHX2 genotype was set the day you were conceived and will not change. So unlike cholesterol or glucose, there is no trend line to follow on this number itself. The point of testing is to learn the variant once, then use it to shape decisions about the markers that do move: blood pressure, lipids, kidney function, glucose, and inflammation.

If you carry a higher-risk variant, the practical response is to track those downstream markers more aggressively. Get a baseline of standard heart, kidney, and metabolic labs now, retest in 3 to 6 months if you are making lifestyle changes, and at least annually thereafter. Carrying a higher-risk variant is not by itself a guideline-endorsed reason to change treatment thresholds, but many clinicians and patients use that information to motivate earlier attention to borderline blood pressure, borderline LDL, or early kidney function changes.

When Genetic Results Can Be Misleading

Genetic testing has its own set of confounders that are different from blood-based tests. Keep these in mind when interpreting an EPHX2 result.

• Variant panel coverage: this test detects the specific EPHX2 variants the assay is designed to find. A result that does not flag a known risk variant does not rule out rare or undescribed changes in the same gene.
• Ancestry-specific effects: the K55R variant raised coronary heart disease risk in Caucasian participants in ARIC, but the same association did not hold in African American participants, and other cohorts have failed to replicate the finding. A result's clinical meaning depends partly on your genetic background.
• Susceptibility, not certainty: EPHX2 variants nudge risk modestly. A higher-risk variant does not mean you will develop heart disease, kidney problems, or any other condition listed here, and a lower-risk variant does not protect you from poor lifestyle, family history, or unrelated risk factors.
• Direct-to-consumer vs clinical-grade differences: some EPHX2 single-letter changes are reported on consumer genetic platforms. The clinical interpretation, quality control, and confirmation pathway differ from a clinical-grade genotype, and the two are not interchangeable.

What to Do With an Unexpected Result

If you carry one or more risk variants, the goal is not to retest the gene. It is to act on the systems EPHX2 touches. Get a comprehensive lipid panel including ApoB and Lp(a), a full kidney function workup including cystatin C and urine albumin-to-creatinine ratio, and inflammatory markers like high-sensitivity C-reactive protein. If you have a personal or family history of stroke, talk with a cardiologist or stroke specialist about whether earlier vascular imaging makes sense.

For people with diabetes or chronic kidney disease, the rs11780592 AA pattern was tied to a sharply higher mortality risk over roughly 7 years, so a positive result here is a reason to be more aggressive about blood pressure, lipids, glucose control, and follow-up, not less. For people planning cardiac surgery, a known gain-of-function K55R variant is worth flagging to the surgical team given the link to postoperative kidney injury.

Because results have implications for biological relatives, consider discussing findings with first-degree family members. A genetic counselor can help interpret a complex result, especially if multiple variants of uncertain meaning show up on the report.