Hereditary Thrombocytopenia

Hereditary thrombocytopenias are a group of rare disorders characterized by a low platelet count caused by genetic mutations. Approximately 10% of all thrombocytopenia cases are hereditary. Unlike acquired forms, these disorders usually manifest in early childhood.

 Clinical symptoms depend on the platelet count. Mild cases may present only with bruising or nosebleeds, while severe cases can cause life-threatening internal hemorrhages. Diagnosis is based on blood tests, bone marrow examination, and genetic testing.

Mild forms often do not require treatment. In cases of significant bleeding, platelet transfusions may be administered, and in the most severe cases, hematopoietic stem cell transplantation may be necessary. In certain situations, medications that stimulate platelet production are used. Drugs that impair platelet function (e.g., aspirin) should be avoided. Splenectomy is generally ineffective.

Main Types

 MYH9-related disorders

These are the most common forms (approximately 1:25,000 – 1:50,000). They are characterized by a low platelet count, large platelet size, and distinctive inclusions in leukocytes. Depending on the subtype (May-Hegglin anomaly, Sebastian, Epstein, or Fechtner syndromes), additional manifestations may include renal disease, hearing loss, or cataracts.

Congenital amegakaryocytic thrombocytopenia (CAMT)

A very rare disorder characterized by a markedly reduced platelet count and absence of megakaryocytes in the bone marrow. It is caused by mutations in the MPL gene and is inherited in an autosomal recessive manner. Bone marrow transplantation is often required.

Thrombocytopenias associated with mutations in RUNX1, ANKRD26, and ETV6 genes

These mutations not only reduce the platelet count but also significantly increase the risk of hematologic malignancies, particularly leukemia.