May-Hegglin thrombocytopenia

May-Hegglin anomaly (also known as May-Hegglin thrombocytopenia, Döhle leukocyte inclusions with giant platelets, or MHA) is a rare inherited blood disorder characterized by three main features: thrombocytopenia (a reduced number of platelets), giant platelets (macrothrombocytopenia), and characteristic Döhle-like inclusion bodies in white blood cells (leukocytes), particularly neutrophils and monocytes. It is caused by mutations in the MYH9 gene, which encodes non-muscle myosin heavy chain IIA. May-Hegglin anomaly is now classified as part of the broader group of MYH9-related disorders, which also includes Sebastian syndrome, Fechtner syndrome, and Epstein syndrome. The condition primarily affects the hematologic system. Many individuals are asymptomatic or have only mild bleeding tendencies, such as easy bruising, prolonged bleeding after surgery or dental procedures, epistaxis (nosebleeds), or menorrhagia (heavy menstrual bleeding) in women. The severity of bleeding symptoms generally correlates with the degree of thrombocytopenia rather than the platelet size. Importantly, some patients with MYH9-related disorders may also develop sensorineural hearing loss, cataracts, and nephritis (kidney inflammation that can progress to renal failure), though these extra-hematologic features are more commonly associated with Fechtner and Epstein syndromes than with classic May-Hegglin anomaly. There is no specific cure for May-Hegglin anomaly. Management is primarily supportive and depends on the severity of symptoms. Patients with mild bleeding may require no treatment, while those with significant bleeding episodes may benefit from platelet transfusions. Desmopressin (DDAVP) or antifibrinolytic agents such as tranexamic acid may be used to manage bleeding. Patients should avoid antiplatelet medications such as aspirin. Regular monitoring for potential complications, including hearing loss and kidney function, is recommended, particularly in individuals with MYH9-related disorders. Genetic counseling is advised for affected families.

Data sourced from FDA regulatory filings and ClinicalTrials.gov. Updated periodically.

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