title: R1933X mutation in the MYH9 gene in May-Hegglin anomaly mimicking idiopathic thrombocytopenic purpura.
abstract: May-Hegglin anomaly (MHA) is a rare autosomal dominant disorder characterized by the triad of thrombocytopenia, giant platelets, and inclusion bodies in leukocytes. Recent evidence links MHA to mutations in the MYH9 gene. MHA has not been reported in Taiwan before. We report a 25-year-old Taiwanese man who presented with prolonged bleeding after dental extraction. Examination of peripheral blood smear revealed thrombocytopenia (platelet = 35,000/μL), giant platelets, and Döhle-like cytoplasmic inclusions in neutrophils. A strong family history of thrombocytopenia favored hereditary macrothrombocytopenia over idiopathic thrombocytopenic purpura (ITP). Electron microscopy revealed a spindle shape and parallel order of filaments in the inclusions, consistent with the diagnosis of MHA. We performed mutational analysis using polymerase chain reaction followed by direct sequence of the MYH9 gene for the patient, his maternal uncle and cousin, and all showed the same heterozygous R1933X mutation in exon 40. MHA should be considered when a young patient has thrombocytopenia, frequently misdiagnosed as ITP. Morphological examination of peripheral blood smear, family history tracing and genetic studies are required to make an accurate diagnosis and avoid unnecessary and even harmful therapies such as corticosteroids and splenectomy.
authors.affiliation: Division of Nephrology, Department of Internal Medicine, Tri-Service General Hospital, National Defense Medical Center, Taipei, Taiwan.
authors.forename: Chih-Chien
authors.initials: CC
authors.lastname: Sung
authors.affiliation: Division of Nephrology, Department of Internal Medicine, Tri-Service General Hospital, National Defense Medical Center, Taipei, Taiwan.
authors.forename: Shih-Hua
authors.initials: SH
authors.lastname: Lin
authors.affiliation: Department of Pathology, Tri-Service General Hospital, National Defense Medical Center, Taipei, Taiwan.
authors.forename: Tai-Kuang
authors.initials: TK
authors.lastname: Chao
authors.affiliation: Division of Hematology/Oncology, Department of Internal Medicine, Tri-Service General Hospital, National Defense Medical Center, Taipei, Taiwan. Electronic address: yeu-chin@yahoo.com.tw.
authors.forename: Yeu-Chin
authors.initials: YC
authors.lastname: Chen
mesh_terms: D000328:Adult; D003937:Diagnosis, Differential; D006801:Humans; D008297:Male; D020409:Molecular Motor Proteins / Q000235:genetics*; D009154:Mutation; D018995:Myosin Heavy Chains / Q000235:genetics*; D016553:Purpura, Thrombocytopenic, Idiopathic / Q000175:diagnosis*; D013921:Thrombocytopenia / Q000175:diagnosis* / Q000235:genetics*
chemical_list: C103814:MYH9 protein, human; D020409:Molecular Motor Proteins; D018995:Myosin Heavy Chains
keywords: MYH9-related disorder; giant platelets; leukocyte inclusions