MYH9‐related disease: Assessment of the pathogenicity of a new mutation

Other common causes of thrombocytopenia were excluded: platelet antibodies detection by flow cytometry or by monoclonal antibody immobilized platelet antigen assay (MAIPA kit, apDia) were negative, thyroid stimulating hormone was normal, antinuclear antibodies and viral serologies for Hepatitis B virus, Hepatitis C virus and human immunodeficiency virus were negative, and there was no lupus anticoagulant. Sequencing analysis revealed a novel c.3131_3151dup p.(Gln1044_Arg1050dup) duplication in exon 25 of MYH9 gene. [...]the presence of these inclusion bodies in granulocytes is not constant. [...]in the case of macrothrombocytopenia, genetic analysis is essential to avoid misdiagnosing MYH9-related disease and delaying the patient's management.