Thrombaszthénia

Thrombasthenia refers to a rare group of inherited bleeding disorders characterized by defective platelet function, leading to impaired blood clotting. The most common form is Glanzmann thrombasthenia (GT), an autosomal recessive condition caused by mutations in the *ITGA2B* or *ITGB3* genes, which encode the glycoprotein IIb/IIIa receptor on platelet surfaces. This receptor is essential for platelet aggregation, the process by which platelets clump together to form clots. Without functional glycoprotein IIb/IIIa, platelets fail to bind fibrinogen effectively, resulting in prolonged bleeding times and an increased risk of spontaneous or traumatic hemorrhage.

Symptoms of thrombasthenia typically manifest in early childhood and may include prolonged bleeding from minor injuries, such as cuts or circumcision, nosebleeds, excessive menstrual bleeding, and delayed clotting after dental procedures or surgeries. Severe cases can lead to life-threatening internal bleeding, such as into joints (hemarthrosis) or organs. Diagnosis involves laboratory tests, including platelet aggregation studies, which show absent or markedly reduced platelet aggregation in response to agonists like adenosine diphosphate (ADP) or collagen. Flow cytometry can confirm the absence of glycoprotein IIb/IIIa on platelet surfaces.

Management of thrombasthenia focuses on preventing bleeding episodes and treating acute hemorrhages. Desmopressin (DDAVP) may be used in mild cases, but the primary treatment is platelet transfusions, which provide functional platelets to support clotting. Emerging therapies, such as recombinant glycoprotein IIb/IIIa or gene therapy, are under investigation for long-term management. Patients with thrombasthenia should avoid medications that impair platelet function, such as nonsteroidal anti-inflammatory drugs (NSAIDs), and receive prophylactic care before invasive procedures.

Thrombasthenia is rare, with an estimated prevalence of 1 in 1 million people, and is more common in populations with a history of consanguinity. Genetic counseling is recommended for affected families to assess recurrence risks. While there is no cure, early diagnosis and appropriate medical intervention can significantly improve quality of life and reduce complications.