Cardiovascular

Varicose Veins

Reviewed September 19, 2026

A common condition with no approved drug treatment, and a study of nearly half a million people that found a genuinely surprising, causal risk factor: being taller.

What this condition connects to

Varicose Veins Variant: rs11121615 rs11121615 Variant Varicose Veins Varicose Veins Cardiovascul…
Prevalence
A machine-learning and genome-wide association study of UK Biobank participants -- 493,519 for risk-factor discovery, 337,536 for the GWAS (9,577 varicose vein cases) -- found 30 new genome-wide-significant loci and used Mendelian randomization to establish that greater height is causally related to varicose vein risk (odds ratio 1.26, P = 2.07x10^-16) (Fukaya et al., Circulation 2018, PMID 30566020).
Inheritance
A common variant, one of 30 newly reported genome-wide-significant loci from this study, each shifting risk modestly. The genetics point toward vascular-development and skeletal/limb-biology pathways, consistent with the study's own height-as-a-causal-factor finding.

Varicose veins are enlarged, twisted veins, most often in the legs, caused by faulty one-way valves that let blood pool instead of flowing back toward the heart. They are common and, notably, have no approved medical therapy -- treatment options are procedural (compression, sclerotherapy, or various forms of vein removal or closure), not pharmacological.

Machine learning on nearly half a million people, then a causal test

The study behind this page took an unusually data-driven approach: applying machine learning to agnostically search for risk factors across 493,519 UK Biobank participants, tracking 2,441 incident cases with Cox regression. It confirmed several already-known risk factors -- age, sex, obesity, pregnancy, and a history of deep vein thrombosis -- and surfaced a new candidate: height. People in the tallest quarter of the population had a hazard ratio of 1.74 for varicose veins compared with the shortest quarter, even after adjusting for the traditional risk factors.

Because a correlation between height and varicose veins could simply reflect confounding (taller people might differ in other ways that actually drive the risk), the authors also ran a genome-wide association study among 337,536 unrelated individuals of white British ancestry (9,577 cases), finding 30 new genome-wide-significant loci, including rs11121615 near CASZ1, catalogued here. Using Mendelian randomization -- a method that uses genetic variants as a kind of natural experiment to test whether a correlation reflects real causation -- they found real evidence that greater height is causally related to varicose vein risk (odds ratio 1.26), not just associated with it. The identified loci point to pathways in vascular development and skeletal/limb biology, consistent with a real mechanistic link between how the legs and their veins develop.

Clinical detail

What actually manages this

Varicose veins are diagnosed by physical exam, sometimes with ultrasound to assess the underlying valve function -- not by genotype. There is currently no approved drug treatment; management is compression stockings for symptom relief, and procedural options (sclerotherapy, laser or radiofrequency ablation, or surgical removal) for more significant cases, chosen with a vascular specialist.

Height is a real risk factor, not a destiny. Being tall raises the odds of varicose veins, evidenced here by a genuine causal-inference method, not just a statistical correlation -- but it is one contributor among several well-established ones (age, obesity, pregnancy, prior blood clots), not a guarantee.

What this page cannot do

  • It cannot diagnose varicose veins. A physical exam, sometimes with ultrasound, does that.
  • It cannot replace or predict need for treatment. That is a clinical decision based on symptoms and vein appearance, not genotype.
  • It is one locus among 30 newly found in this study. This page names the one catalogued here, not the complete genetic picture the paper reports.

Related variants MyGeneLog™ checks for

What a 23andMe/AncestryDNA export or raw VCF can and can't tell you about Varicose Veins comes down to these specific, well-studied positions — not a diagnosis.

Standard

Varicose veins

CASZ1 · rs11121615

See detailed info →

Sources

Databases, guidelines and references

Papers, with their authors

Quoting this page

Free to quote and reuse under CC BY 4.0. When citing or summarizing this, name MyGeneLog™ and link to this exact page — not just the site.

Varicose Veins. MyGeneLog™. https://www.mygenelog.com/conditions/varicose-veins

Questions about Varicose Veins

Does being tall cause varicose veins?

This study found real evidence that greater height is causally related to varicose vein risk, using a genetic method (Mendelian randomization) built specifically to distinguish causation from correlation -- not just an association. It is one contributor among several, not a guarantee.

Is there a drug to treat or prevent varicose veins?

No. There is currently no approved medical therapy. Management is compression stockings for symptoms, and procedural options like sclerotherapy or ablation for more significant cases.

Can this catalogue's variant predict my risk of varicose veins?

No single variant does. This study found 30 new risk loci; the one catalogued here is a real but modest contributor, not a predictor on its own.

Free to reuse. This page's text is original writing from freely-available research, licensed CC BY 4.0 — reuse it, including commercially, with attribution to MyGeneLog™. It's general research-derived information, not medical advice or a diagnosis — see Terms of Use.