rs1800386 — VWF Tyr1584Cys

Von Willebrand Factor Tyr1584Cys — A Low-Penetrance Bleeding Risk Variant

Von Willebrand factor (VWF) is the central hemostatic protein that acts as both a molecular glue — binding platelets to damaged vessel walls — and a carrier protein that shields coagulation Factor VIII from degradation. The Tyr1584Cys variant¹¹ Tyr1584Cys variant
Tyrosine to cysteine substitution at position 1584 of the VWF preprotein; located in the D4 domain is a missense change in VWF that affects how quickly the protein is cleared from the bloodstream. Carriers have lower circulating VWF levels, and when those levels fall below the threshold required for effective hemostasis, the result is von Willebrand disease type 1 (VWD type 1)²² von Willebrand disease type 1 (VWD type 1)
The most common inherited bleeding disorder, affecting 1-2% of the general population; type 1 is a quantitative deficiency — not enough VWF, but what's there functions normally — the mildest and most prevalent form of the disease. However, the variant is notable for its incomplete penetrance³³ incomplete penetrance
Penetrance: the fraction of variant carriers who actually develop the expected trait. A penetrance of 24% means three-quarters of carriers have normal VWF levels and no symptoms — only about one in four heterozygous carriers has measurably reduced VWF antigen levels.

The Mechanism

The p.Tyr1584Cys substitution introduces a free cysteine residue into the D4 domain of VWF. Studies using VWF propeptide-to-antigen ratios⁴⁴ Studies using VWF propeptide-to-antigen ratios
Elevated propeptide/antigen ratio is the biochemical fingerprint of enhanced VWF clearance; it indicates the protein is being secreted at a normal rate but removed from circulation faster than normal show that carriers have VWF being cleared from circulation faster than it is produced. This is distinct from a secretion defect — the bone marrow and endothelial cells produce VWF normally, but macrophages and other clearance receptors (including CLEC4M/LSECtin and LRP1) remove the structurally altered protein more aggressively. The net effect is chronically lower-than-average VWF antigen levels, with the degree of reduction varying substantially between individuals due to genetic modifiers.

ABO blood group is the most important modifier: blood group O individuals naturally have VWF levels 25-30% lower than non-O individuals⁵⁵ blood group O individuals naturally have VWF levels 25-30% lower than non-O individuals
ABO-O effect is independent of any VWF mutation; it operates via reduced VWF survival in plasma due to faster VWF clearance mediated by carbohydrate structures on the protein. A p.Tyr1584Cys carrier with blood group O therefore faces a compound reduction in VWF from two independent mechanisms, substantially increasing the probability that their VWF falls into the diagnostic range for VWD.

The Evidence

A 2025 GWAS of 926 individuals with VWF:Ag ≤50 IU/dL⁶⁶ 2025 GWAS of 926 individuals with VWF:Ag ≤50 IU/dL
Friedman et al. for the TOPMed Consortium; validated in 5 biobanks including FinnGen; 12,846 controls; published in J Thromb Haemost produced the definitive quantification of this variant's effect: an odds ratio of 78.58 for having low VWF antigen levels. Despite this dramatic association, actual VWD diagnosis occurred in only 0.3% of heterozygous carriers (OR 7.16 for diagnosis, with a penetrance of just 24.2% for even the VWF:Ag ≤50 threshold). This combination — large biochemical effect, modest clinical penetrance — is the hallmark of a low-penetrance pathogenic variant modified by environment and other genetics.

The same study documented meaningful bleeding-related consequences among carriers: heavy menstrual bleeding (OR 1.27), iron deficiency anemia (OR 1.55), and intrapartum hemorrhage (OR 2.20)⁷⁷ heavy menstrual bleeding (OR 1.27), iron deficiency anemia (OR 1.55), and intrapartum hemorrhage (OR 2.20)
These associations were statistically significant in both discovery and replication cohorts. A possibly surprising finding is a protective effect against deep vein thrombosis (OR 0.54) — the lower VWF levels that create a bleeding liability simultaneously reduce the risk of pathological clot formation.

A detailed 2024 laboratory study⁸⁸ detailed 2024 laboratory study
Christopherson et al. (Zimmerman Project Investigators); 58 p.Y1584C carriers with no other known VWF mutations compared to wild-type VWF individuals confirmed the clearance mechanism by demonstrating elevated propeptide/antigen ratios and lower mean VWF:antigen and VWF:ristocetin cofactor activity values in carriers, alongside significantly more abnormal bleeding scores.

Practical Implications

For most carriers, the actionable step is awareness combined with targeted testing — not blanket treatment. VWF activity (VWF:Ag and VWF:ristocetin cofactor) can be measured with a simple blood draw. If levels are low (below 50 IU/dL), a hematologist can assess whether the bleeding score warrants prophylaxis or preparation for high-risk procedures and deliveries.

Desmopressin (DDAVP)⁹⁹ Desmopressin (DDAVP)
A synthetic analog of vasopressin that triggers release of stored VWF from endothelial cells; effective for VWD type 1 with a clearance mechanism because it acutely raises VWF levels is the first-line intervention for symptomatic VWD type 1. A DDAVP challenge test administered by a hematologist establishes whether a carrier responds adequately to cover surgical or obstetric bleeding risk. For carriers who do respond, intranasal or IV DDAVP is available for planned use before invasive procedures.

Women of reproductive age are the highest-priority group for evaluation because both menstrual blood loss and delivery carry significantly elevated bleeding risk in carriers. Carriers planning surgery or invasive dental procedures (particularly tooth extractions) should alert their surgical team so that VWF levels can be assessed and coverage planned.

Interactions

The ABO blood group is the most clinically significant modifier of this variant's penetrance. Carriers who also carry blood group O (rs505922 TT genotype marks blood group O status) face a compound reduction in VWF from two independent clearance mechanisms; this combination substantially increases the probability of VWF:Ag falling below 50 IU/dL and meeting criteria for VWD type 1 diagnosis.

The variant also sits in the context of coagulation balance: the reduced VWF levels that create bleeding liability simultaneously lower thrombosis risk. Carriers with inherited thrombophilias (such as Factor V Leiden, rs6025, or prothrombin G20210A, rs1799963) may find that the VWF reduction partially counteracts elevated clotting risk, though this trade-off is not a substitute for specialized management of either condition.