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Clinical manifestation and molecular genetic characterization of MYH9 disorders

Dana Provaznikova1, Vera Geierova, Tereza Kumstyrova

  • 1Institute of Haematology and Blood Transfusion, Prague, Czech Republic. dana.provaznikova@uhkt.cz

Platelets
|June 27, 2009
PubMed

Insights

The MYH9 gene causes May-Hegglin anomaly and related disorders, characterized by giant platelets and other symptoms. Genetic analysis confirmed mutations in most patients, linking MYH9 mutations to these distinct conditions.

Area of Science:

  • Genetics
  • Hematology
  • Molecular Biology

Background:

  • May-Hegglin anomaly (MHA), Sebastian (SBS), Fechtner (FTNS), and Epstein (EPS) syndromes are distinct disorders.
  • These conditions share common symptoms like giant platelets, thrombocytopenia, granulocyte inclusions, deafness, cataracts, and renal failure.
  • All are caused by mutations in the MYH9 gene, which encodes non-muscle myosin heavy chain IIA (NMMHC-IIA).

Purpose of the Study:

  • To investigate the genetic basis of MYH9-related disorders.
  • To correlate MYH9 gene mutations with clinical manifestations.
  • To analyze platelet surface glycoproteins in patients with MYH9 mutations.

Main Methods:

  • Immunostaining of NMMHC-IIA in blood samples from 15 patients.
  • Polymerase chain reaction (PCR) analysis of selected MYH9 gene exons.
  • Comparison of fluorescence and mutational analysis with clinical data.
  • Determination of platelet glycoprotein site numbers.

Main Results:

  • Mutations in the MYH9 gene were identified in nine out of 15 patients, including one novel mutation.
  • A correlation was established between MYH9 mutations and the observed clinical phenotypes.
  • Most patients exhibited an increased number of platelet glycoproteins, potentially linked to larger platelet size.

Conclusions:

  • MYH9 gene mutations are the underlying cause of MHA, SBS, FTNS, and EPS syndromes.
  • Genetic analysis of MYH9 is crucial for diagnosing these related disorders.
  • Increased platelet glycoproteins may be a consequence of the enlarged platelet size characteristic of MYH9-related conditions.

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