NOS3 rs17672135: What Your Genotype Means
The rs17672135 variant is located in the NOS3 gene, which encodes endothelial nitric oxide synthase. Some research suggests a statistical association between this variant and an increased risk of preeclampsia in pregnant women.
What each genotype means
Typical preeclampsia risk
This genotype is considered the reference state in studies examining the association between the NOS3 gene and pregnancy-related vascular health. It does not show the increased risk of preeclampsia associated with the T allele in some clinical research.
This is a common genotype in most populations.
Potentially increased risk
Some research suggests that carrying the T allele may be associated with an increased risk of preeclampsia, a condition involving high blood pressure during pregnancy. Evidence is mixed across different populations, and you should discuss any concerns regarding pregnancy health with your obstetrician.
This genotype is found at varying frequencies depending on ancestral background.
Higher preeclampsia risk
Studies have identified an association between this homozygous genotype and an increased risk of preeclampsia compared to those without the T allele. Because this association is based on statistical trends in specific cohorts, it is not a diagnostic tool; please consult your healthcare provider for personalized prenatal care.
This genotype is less common and varies significantly by ancestry.
The Role of the NOS3 Gene
The NOS3 gene provides instructions for making an enzyme called endothelial nitric oxide synthase (eNOS). This enzyme is responsible for producing nitric oxide, a molecule that plays a critical role in maintaining the health of blood vessels by helping them relax and dilate, which regulates blood pressure. During pregnancy, the proper function of eNOS is vital for healthy blood flow to the placenta and the developing fetus. Variations in the NOS3 gene, such as rs17672135, have been studied to determine if they alter the production or function of this enzyme. Because nitric oxide is essential for vascular health, researchers hypothesize that genetic changes affecting its production could potentially influence the risk of hypertensive disorders during pregnancy, such as preeclampsia. However, the biological impact of specific SNPs remains a subject of ongoing investigation.
Research on Preeclampsia Risk
Preeclampsia is a complex, multifactorial condition characterized by high blood pressure during pregnancy. Several studies have investigated whether the rs17672135 variant contributes to this risk. Some research has reported a significant association, particularly under a recessive genetic model, where individuals with the homozygous minor allele (T/T) may show an increased statistical risk of developing preeclampsia. Other studies, however, have found no significant association, highlighting the complexity of genetic research in this area. It is important to note that these findings are often based on case-control studies, which can be limited by sample size and population-specific factors. Because preeclampsia is influenced by a combination of genetic, environmental, and lifestyle factors, a single SNP is rarely a definitive predictor of disease. The evidence for this variant is considered moderate, and results have not been consistently replicated across all ethnic groups.
Clinical Context and Limitations
If you are pregnant or planning a pregnancy, it is crucial to understand that genetic testing for variants like rs17672135 is not a standard clinical tool for predicting preeclampsia. The statistical associations observed in research studies do not translate into individual medical diagnoses. Many women with the 'risk' genotype will have healthy pregnancies, and many women without it may still develop preeclampsia. You should never use genetic information to guide medical decisions or to alter your prenatal care. If you have concerns about your risk for preeclampsia, please discuss them with your obstetrician or healthcare provider. They can assess your clinical risk factors—such as blood pressure history, age, and body mass index—which are far more reliable indicators for managing your health during pregnancy. Always rely on professional medical guidance for any concerns regarding your pregnancy.
How common is this variant?
The frequency of the rs17672135 variant varies significantly by ancestry, and its distribution is not uniform across global populations.
Frequently asked questions
Does having the TT genotype mean I will get preeclampsia?
No. Genetic associations are statistical, not predictive. Having a specific genotype does not guarantee that you will develop a condition, and many other factors influence pregnancy health.
Should I get tested for this variant?
There is no clinical recommendation to test for this variant. It is not used in routine prenatal care to assess individual risk for preeclampsia.
What are the main risk factors for preeclampsia?
Known risk factors include a history of preeclampsia, chronic hypertension, diabetes, obesity, and maternal age. Consult your doctor to discuss your personal risk profile.
Can I take supplements to offset this genetic risk?
You should not take any supplements or medications based on your genetic results. Always consult your obstetrician before taking any supplements during pregnancy.
Sources & further reading
Educational information only, last refreshed 11/6/2026. Not medical advice — these associations describe population statistics, not individual predictions.
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Promoter variant (-786T>C) in the NOS3 gene associated with endothelial nitric oxide synthase expression and cardiovascular risk.
Also known as Glu298Asp (894G>T), this variant affects endothelial nitric oxide synthase cleavage and vascular tone, modulating exercise-induced vasodilation and aerobic performance.
An intronic endothelial nitric oxide synthase polymorphism that influences vascular tone, exercise-induced vasodilation, and aerobic endurance performance.
Commonly studied variant in the endothelial nitric oxide synthase gene, associated with cardiovascular traits.
Endothelial nitric oxide synthase variant implicated in blood flow response and muscle capillarization during aerobic training.
Promoter-adjacent polymorphism affecting endothelial nitric oxide synthase transcription, modulating exercise-induced vasodilation and aerobic trainability.