Protein S deficiency

Protein S deficiency is a rare genetic disorder characterized by an increased risk of venous thromboembolism, which includes conditions such as deep vein thrombosis and pulmonary embolism. The disorder is named after Protein S, a naturally occurring anticoagulant in the body that prevents the formation of excess blood clots. In individuals with Protein S deficiency, there is a reduced level or function of this protein, leading to an increased risk of clot formation.

Causes[edit | edit source]

Protein S deficiency is usually inherited in an autosomal dominant manner, meaning that an affected individual has a 50% chance of passing the disorder to each of their children. The disorder is caused by mutations in the PROS1 gene, which provides instructions for producing Protein S. There are two forms of the disorder: Type I, which is characterized by low levels of Protein S in the blood, and Type II, where the protein is present but not functioning properly.

Symptoms[edit | edit source]

The primary symptom of Protein S deficiency is an increased risk of developing abnormal blood clots. These clots can lead to serious conditions such as deep vein thrombosis, where clots form in the deep veins of the body, usually in the legs, and pulmonary embolism, where a clot travels to the lungs. Other symptoms can include skin necrosis, where skin tissue dies due to a lack of blood flow, and purpura fulminans, a severe clotting disorder that can cause skin necrosis and systemic blood clots.

Diagnosis[edit | edit source]

Diagnosis of Protein S deficiency is typically made through a blood test that measures the level and function of Protein S in the blood. Genetic testing may also be performed to identify mutations in the PROS1 gene.

Treatment[edit | edit source]

Treatment for Protein S deficiency is primarily focused on preventing the formation of blood clots. This can include the use of anticoagulant medications, such as warfarin, and lifestyle modifications to reduce the risk of clot formation. In severe cases, plasma infusion may be used to increase the level of Protein S in the blood.