ClinGen Actionability PROS1
This is a genotype with recommended actions if clinically confirmed. In brief:
- Thrombophilia due to protein S deficiency (PROS1) is characterized by reduced or absent coagulation activity.
- Partial PROS1 deficiency (heterozygous forms) can lead to an increased risk of venous thromboembolism (VTE), commonly a deep vein thrombosis (DVT) of the lower limbs with or without pulmonary embolism (PE).
- Heterozygotes usually have no symptoms until adulthood. VTE events are mainly provoked by factors such as surgery, pregnancy, immobilization, or exogenous hormone use. Antithrombotic prophylaxis might be be effective in reducing stroke risk.
- Following a cerebral venous thrombosis (CVT) or cerebral venous and sinus thrombosis (CVST) individuals with protein S deficiency should be considered for indefinite anticoagulation. Individuals with thrombophilia (including protein S deficiency) have an increased risk of VTE (2-5%; adjusted HR, 4.71; 95% CI: 1.34-16.5) following an index CVT.
- Perioperative VTE prophylaxis is recommended for patients with PROS1 deficiency during and after gynecological surgery
- Based on the increased risk of VTE, all pregnant women with an inherited thrombophilia should be referred to a local expert and undergo individualized risk assessment which may modify pregnancy management decisions; see detailed recommendations in the full ClinGen document (URL below).
- Thrombophilic disorders (including PROS1 deficiency) are contraindications for the use of estrogen containing prescription drugs approved for the prevention of postmenopausal osteoporosis.
- Patients with severe PROS1 deficiency (homozygous or compound heterozygous forms with undetectable PROS1 levels) typically manifest several hours to days after birth and may develop purpura fulminans, a life-threatening condition involving severe clotting throughout the body and causing necrosis of tissues.
The full ClinGen Actionability report about thrombophilia due to protein S deficiency (PROS1) can be found here.
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