From the Guidelines
May-Hegglin anomaly cannot be diagnosed using flow cytometry alone, and a definitive diagnosis requires a combination of peripheral blood smear examination and genetic testing. May-Hegglin anomaly is a rare genetic disorder characterized by thrombocytopenia, giant platelets, and leukocyte inclusions called Döhle bodies. While flow cytometry can be used to evaluate platelet glycoproteins and procoagulant activity, as described in the study by Gresele et al. 1, it is not sufficient for diagnosing May-Hegglin anomaly. The study recommends expanded flow-cytometry to evaluate glycoproteins such as GPIa/IIa, GPIV, and GPVI, but this is for identifying rarer platelet glycoprotein abnormalities, not specifically for May-Hegglin anomaly. Some key points to consider in the diagnosis of inherited platelet function disorders include:
- Peripheral blood smear examination to identify characteristic Döhle bodies in neutrophils and giant platelets
- Genetic testing for mutations in the MYH9 gene to confirm the diagnosis
- A combination of complete blood count, peripheral blood smear examination, and genetic testing is typically used for diagnosing May-Hegglin anomaly, rather than flow cytometry alone. As noted in the study by Gresele et al. 1, transmission electron microscopy and other tests may be recommended for counting platelet a- or dense-granules and identifying structural alterations, but these are not specific for May-Hegglin anomaly. It is essential to use a combination of diagnostic tests to ensure accurate diagnosis and avoid misdiagnosis, which could lead to unnecessary treatments.
From the Research
May-Hegglin Anomaly and Flow Cytometry
- May-Hegglin anomaly is a rare hereditary condition characterized by thrombocytopenia, giant platelets, and inclusion bodies in leukocytes 2.
- The diagnosis of May-Hegglin anomaly can be missed, and its frequency is probably underestimated 2.
- Flow cytometry has been used to study platelet surface glycoproteins in patients with May-Hegglin anomaly and Sebastian syndrome, and has identified a defect of the GPIb/IX/V complex in the whole platelet population and in the subpopulation of large platelets 3.
- Flow cytometry has also been used to study the expression of P-selectin and active integrin αIIbβ3 on platelets from patients with May-Hegglin anomaly, and has shown background platelet activation and partial platelet refractoriness to stimulation 4.
- The use of flow cytometry in the diagnosis of May-Hegglin anomaly can help to identify patients with this condition and to distinguish it from other disorders, such as heterozygous Bernard-Soulier syndrome 3.
Clinical Features and Laboratory Findings
- Patients with May-Hegglin anomaly may experience bleeding diathesis, ranging from severe to absent, and platelet count can range from 26 to 178 x 10(9)/L 2.
- The in vitro function of platelets in patients with May-Hegglin anomaly is normal except for the absence of shape change in all subjects and defective response to epinephrine in some patients 2.
- Electron microscopy has revealed giant platelets with multiple filopodia and fusion of α-granules with dilated open canalicular system, containing filamentous and vesicular inclusions 4.
- The diagnosis of May-Hegglin anomaly should be suspected whenever a patient has a low platelet count or a bleeding diathesis of unknown origin 2.
Differential Diagnosis and Treatment
- May-Hegglin anomaly should be considered in the differential diagnosis of chronic thrombocytopenia associated with large platelets, including chronic idiopathic thrombocytopenic purpura 5.
- Failure to appropriately diagnose May-Hegglin anomaly could result in inappropriate treatment 5.
- Desmopressin infusion has been shown to greatly shorten the bleeding time in patients with May-Hegglin anomaly 2.
- The identification of a GPIb/IX/V defect in May-Hegglin anomaly platelets raises the question of the differential diagnosis from heterozygous Bernard-Soulier syndrome 3.