Abstract

May–Hegglin anomaly (MHA), also known as Döhle leukocyte inclusions with giant platelets and macrothrombocytopenia with leukocyte inclusions, is a rare genetic disorder of the blood platelets that causes them to be abnormally large.

Presentation

In the leukocytes, the presence of very small rods (around 3 micrometers), or Döhle-like bodies can be seen in the cytoplasm.

Pathogenesis

MHA is believed to be associated with the "MYH9" gene. The pathogenesis of the disorder had been unknown until recently, when autosomal dominant mutations in the gene encoding non-muscle myosin heavy chain IIA ("MYH9") were identified. Unique cytoplasmic inclusion bodies are aggregates of nonmuscle myosin heavy chain IIA, and are only present in granulocytes. It is not yet known why inclusion bodies are not present in platelets, monocytes, and lymphocytes, or how giant platelets are formed. "MYH9" is also found to be responsible for several related disorders with macrothrombocytopenia and leukocyte inclusions, including Sebastian, Fechtner, and Epstein syndromes, which feature deafness, nephritis, and/or cataract. MHA is also a feature of the Alport syndrome (hereditary nephritis with sensorineural hearing loss).

Treatment

In many cases, MHA requires no treatment. However, in extreme cases, blood platelet transfusions may be necessary

History

MHA is named for German physician Richard May (January 7, 1863 – 1936) and Swiss physician Robert Hegglin. The disorder was first described by Richard May in 1909 and was subsequently described by Robert Hegglin in 1945.